Best way to get platinum first make creeds with every single one decide which will be your final one for ending before you beat it.
Next level up your favorite creed to max level for max creed trophy
For guide information use these.
Information guide.
http://saltandsanctuary.wiki.fextralife.com/Salt+and+Sanctua...Walk through guide
After doing all this you should be left with two trophies beating the game on New game plus for the alternate ending and platinum for getting all trophies which should be easy if you know what your doing.
Almost forgot to beat The Unspeakable Deep heres a video to help you out.