Mostly depends on the game. Not counting exclusives that obviously have to be played on the specific system, if it's a shooter, third or first, I'll play on PC, because it's better with a mouse. These days I try to play my 2D platformers on Switch, because that style of game can be good on the go, though that's not always a guarantee (Bloodstained ended up being bad on Switch). PS4 is then for kinda anything else as if I beat the game and don't want to keep it, I'll trade or sell it off.