@SaltyLasagna
I don't have a set method or anything, and I never looked up what the "right" way to write chord progressions is so I wouldn't count too much on my advice lol
but basically I start with the idea of the song I want, and the tone I want to set. It could be a sad song with a happy song, or a complicated song with a super simple and basic tune
Then I pick a strumming pattern that fits that tone and start playing some random ass chords. If the chords I play don't match the rhythm or tone of the song I want, I try a different set of chords. If I find I few that I like, I use those chords and either stop there or pick a few more chords that sound nice with the rest.