So two controllers + one PC and you can couch co-op yourself.

I'm using a steam controller on right hand and dual-sense on left,

It started as a way to boost myself, using my ice skele mages on my infernalist to clear the way. But POE2 has auto aim with controller, you can easily assign skills to the shoulder button and fire whilst walking.

So currently I'm using an attack skill on both stormweaver and infernalist whilst the skele mages freeze and kill. Ranged + Summoner is probably a good combo to go with, also builds that require one button will be easier to control.