Learned a trick of a trophy hunting youtuber. Just create a new profile on your PS4, just skip signing it in. Finish the game, delete the profile where your account is signed into and sign it onto this account. It will sync your trophies to your account.
This only works for offline games tho, since you won't have a connection because you are not signed in.
I kind of only do it for games I'm afraid are too hard to finish. If I do finish it in the end I can sync them up. If i gave up it won't stain. With games with online trophies there is no choice.
He even made a topic here on the forums.
I got 2600ish trophies currently. About rank 84k ish I think. Got 3 games finished that aren't synced tho.