I thought this was gonna be a "freedom as in America" thread, and am a little disappointed as I had a perfect suggestion. I'm going to make it anyways because I'm enjoying it and have never seen anyone talk about it.
Helldivers is a fun couch co-op game you can get used for like $15. It was originally a DLC-fest e-shop game, but getting the physical version gets you everything and it's a pretty complete package. You and 3 friends become members of the AMERICAN version of Space Marines and travel the universe fighting degenerate human cyborgs, not-Zerg/Tyranids, and not-Protoss/Chozo/Aperture Science in the name of spreading DEMOCRACY from your home planet of SUPER EARTH.
Plenty of weapons and special abilities, lots of co-op teamwork to be had, vehicles that are actually fun to use, and objective-based gameplay that rewards you for not being a moron and picking fights with everything you see. Enemies are unlimited and you win by completing map-based objectives, so you have to be smart and sneaky to evade patrols until you get to the objective and can Go Loud. Every stage ends with having to call for extraction and hold the perimeter in pitched combat as your dropship closes distance, so there's still no lack of combat.
Special abilities range from placable assets (holy shit the auto turrets are nasty), calling in air/orbitalstrikes, summoning vehicles (including mecha), and support options like scanner drones. Grenades are complimentary. There are enough options that you can more or less build yourself into a dedicated team role, like medic or heavy weapons or whatever else. Reasonable aesthetic customization as well, as long as you like yellow/brown and don't care about not seeing your character's face ever.
I'm only about 5 hours in, but it's the best $15 I've spent on a vidya in the past couple years.
No idea how the online is, because fuck Playstation+. There seems to be some kind of implied continuous metagame of pushing the alien species back, but I don't interface with the system so I don't really know how it works.
Polite sage for unsolicited shilling.