2 player free online games?

My partner and I are currently transitioning to a long distance relationship. He has to travel for work. We were playing Split Fiction and It Takes Two on my PS5 before he left.

We are looking for free online cross compatible games we can play without buying a Playstation plus subscription.

We are absolutely open to suggestions for other games that you do need the Playstation plus subscription for as well but for the next month money is extremely tight. So we are looking for free games we can play on his Xbox and my Playstation. Any suggestions?