I spent roughly a week and a half playing this game, totally an estimated 55 hours. Through this venture, I have an updated understanding of which trophies are obtainable, which are technically obtainable but probably not worth it, and those that are completely unobtainable. With the servers being open until December, this rare platinum is still possible for those already with the unobtainable trophies and a desire for glory.
Micro-transactions have been removed from the game. This is the wild west! The MUT game mode is centered around micro-transactions, so you are entering a weird landscape.
No distinct time estimate. Because all MUT trophies are centered around opening packs, your time spent will come down to EA luck.
Unobtainable trophies prevent you from getting the platinum.
YOU WILL MORE THAN LIKELY NEED 2 PS3S FOR MUT TROPHIES IN 2020
Giver - Post a piece of content to Madden Share
Taker - Download a piece of content from Madden Share
Quality Gift - Download 3 pieces of content from Madden Share
Feedback - Rate a piece of content you've downloaded from Madden Share
Madden Share lost its support around July 2017, and no one has gotten these legitimately since then
Flying Solo - Win a MUT Solo Challenge
MUT Solo Challenges lost their support around December 2019, and no one has gotten it legitimately since then
Going for Gold - Earn Gold from a drill inside the Skills Trainer
QB Camp - 100% completion of all passing drills inside the Skills Trainer (All gold medals)
Stick Skills - 100% completion of all rushing drills inside the Skills Trainer (All gold medals)
Defense Wins Championships - 100% completion of all defensive drills inside the Skills Trainer (All gold medals)
Knowledge is Power - 100% completion of all pre-play drills inside the Skills Trainer (All gold medals)
Happy 25th Madden - Score 25+ points in one game and celebrate 25 years of Madden Football (no SuperSim, OTP, or Co-Op)
Verizon MVP - Combine for 75 points total, with your opponent (no SuperSim, OTP, or Co-Op)
The New Breed - Score a rushing and passing TD with a QB in a single game (no SuperSim, OTP, or Co-Op)
College Influence - Score a TD on an option play (no SuperSim, OTP, Skill Trainer, Practice, or Co-Op)
Unstoppable - Truck a defender during a run (no SuperSim, OTP, Skill Trainer, Practice, or Co-Op)
Arm's Length Away - Stiff arm a defender during a single run (no SuperSim, OTP, Skill Trainer, Practice, or Co-Op)
All offline trophies are still perfectly obtainable, and likely always will be. These require a myriad of doable tasks that shouldn't take too long. Maybe focus on online first!
Get Your Feet Wet (online) - Complete an online ranked head to head game.
Only Seventeen (online) - Score 17+ total points in online ranked head to head games.
Nice Round Number (online) - Score 34+ total points in online ranked head to head games
Online Head to Head is still online as of October 2020. I believe servers are online until December 2020. All you need are 34 points total across all games, not 34 in one game.
Beginning the Journey (online) - Win a MUT Seasons game.
It's Still Easy (online) - Create a MUT team.
MUT is also still online! Build your team to get It's Still Easy, and win a game to Begin your Journey.
Blaine Gabbert - Walter Payton Legacy Award Trophies
All of these trophies are still obtainable, as this is an offline mode.
From the playstationtrophies.com guide by CODEx Vip3r (aka the first person to platinum the game):
Once you have downloaded or created a roster with 99 overall players, make sure that it is currently your active roster then go into Connected Career mode. Choose to do the CCM as a Coach with a Motivation focus and make sure you have Salary Cap off, put your difficulty to All-Madden and 7-minute quarters now leave everything else at their defaults. Sim every game for 3 seasons and you should get this trophy, along with all the other Connected Career trophies, by the time you win your third Super Bowl. Don't worry about losing any games because your 99 rated team can't be beaten.
Playoffs?! - Make the playoffs in Ultimate Team Seasons.
Well Rested - Earn a first round bye in Ultimate Team Seasons.
Complete the Journey - Win a MUT Seasons Super Bowl.
EASILY boosted in 2020. Because 2 ps3s is virtually the only way to get some of these other trophies, these will come naturally while grinding out Lombardi packs. If you don't care about/already have some of the other MUT trophies, find a boosting partner in Gaming Sessions to knock these rare trophies out.
Mr. Suitcase*- Complete a MUT collection.
This is one of three trophies that are likely to give you a giant headache. This trophy requires you to complete one of the thousands of card collections available in MUT mode. HOWEVER.... only one kind of collection is still possible in 2020: Loyalty collectibles. These come out of Lombardi packs, and range anywhere from collecting 1 thing to collecting 48 things. It is entirely luck based; you could pull a 0/1 needed within the first few packs, or you could take thousands of packs to get a single collection. The only way to get Lombardi packs is to make the playoffs and win the Super Bowl.... over and over again. You will more than likely need two ps3s and two copies of the game ($6 amazon) for you to realistically get this trophy.
UPDATE 10/9/20: I just got the 0/1 collectible out of a Lombardi pack, which could have happened within playing a few seasons. My grand total is 1032 games won against my dummy account. I also got to rank 601 on the MUT Seasons Leaderboards.
You Know the Business - Build a MUT team with a team chemistry of 30.
Really Clicking - Build a MUT team with a team chemistry of 70.
Completely Gelled - Build a MUT team with two team chemistry ratings at 60.
This One is Hard 3.0 - Build an 85 rated MUT team.
These trophies are still obtainable, albeit requiring a lot of grinding the above method. When you complete each season in MUT online, you get 2 lombardi packs and 4 reward packs per season (once you reach the All-Madden ranks). The Lombardi packs contain collectibles, but the reward packs contain silver/gold contracts (which can be funneled over to dummy account) and a gold player ranged anywhere 68-88. Eventually, you will get enough players above 85 and pop This One is Hard 3.0, which means you now have access to two chemistries. Now, the overall rating doesn't matter. Form a team where every player has the same chemistries (I am currently on 69 Short Run and 63 Zone Defense) to get Completely Gelled and You Know the Business. You should also get Really Clicking, as getting to 70 only requires getting every player on either offense or defense to be on the same chemistry (I estimate fulfilling these requirements around 700-800 wins).
The Mogul - Win a MUT auction.
Will likely require a boosting partner in 2020, as randoms are inconsistent at posting on the auction board. Simply win an auction.
GOOD LUCK HUNTERS!!!! Hope this is helpful