If you like FPS’s but also like a variety of mission types and being able to scale the difficulty, my suggestion is Deep Rock Galactic. Fantastic game… one of my friends and I play it every weekend. Takes about 30 minutes for the average two-player mission, up to maybe 45 at longest, so you can easily block out playtime.

Also, in general, regardless of what you’re playing… you don’t really need a LAN to play together, you can just friend each other on Steam and easily join each other’s games that way. Even if you’re both in your own residences, the voice chat tool in Steam is great for talking while playing games.

Yeah, I have a few recommendations! I haven’t done peer to peer intranet connecting, but I have done the multiplayer for these games that are pretty accessible price and resource wise and are fun to play with friends:

• Rocket League ($0) - a fantastic co-op or versus game involving a neat concept of rocket powered car soccer. It may take a while to get use to the controls/concept, but I’ve sunk a large number of hours into it! It also has a pretty good training mode and AI exhibition matches to get you up to speed.

• Marvel Rivals ($0) - a new release hero shooter in Marvel Comics fashion. Has some teamwork and strategy in its 6v6 games and is an accessible into into hero shooters.

• Portal 2 ($10) - one of my favorite games ever. Its a story driven puzzle game involving spacial vending portals. Can be played co-op and it a very fun experience single player or with others.

• Overwatch 2 ($0) - see marvel rivals, as this came out first.

• CSGO ($0) - a classic multiplayer shooter with a long time following.

• Helldivers 2 ($40) - modern bullet hell Coop shooter against lore specific aliens and robot enemy hordes.

• Battelbit Remastered ($15) - battlefield-esque shooter gameplay with big maps, small battalions within larger teams, and vehicles. Indie dev.

• Ultimate chicken horse ($15) - a very fun single device coop thats a combative platformer. Great with groups, and it says it supports online play.

• Divinity Original Sin / DOS2 / Baldurs Gate 3 - all fantastic co-op fantasy RPGs that can be paused and picked up whenever. BG3 is the most recent and is very well critically acclaimed.

In terms of your connection, LAN and WAN isn’t really going to be the way to go except for some very specific scenarios.

The Steam Deck and almost all multiplayer games connect via Internet servers and your steam accounts. Some games you can host and your friend connects directly via the Internet - games are designed to support that so you often don’t need to resort to local LAN/WiFi play.

It doesn’t matter that you’re next door to each other - you might as well be miles away from each other for all it matters - you both just need good stable internet connections to the remote servers, with decent speed and your Internet routers not too restrictive on your connections (firewalls not blocking access, relevant ports open).

So basically ensure you have a good WiFi connection. Even better you can also get USB c ethernet dongles or a dock for your steam deck with ethernet to connect to your router directly and avoid WiFi.

I play with my steam deck docked under the TV, ethernet connection to my router, hdmi to my TV and an xbox controller and Bluetooth headphones. I play on the couch with all the benefits of the steam deck.

Both of you docking your steam decks with ethernet connections to your Internet routers may give you a better experience.

Edit: In terms of games to try:

• Phasmophobia - you can cooperatively try and hunt ghosts, horror game but can be a lot of fun

• Keep talking and nobody explodes - coop game where you diffuse a bomb, hectic but not needing fps reactions

• Divinity: Original Sin 1 & 2 - RPG games which can be played in Co op mode, with tactical combat

• Baldurs Gate 3 - similar to above, same makers but hugely popular and highly regarded game

• Valheim - coop survival game - explore and build a base, defeats bosses etc

• Stardew Valley - super cosy farming sim, with simple combat. It’s a very chill multiplayer experience - can just chat away (or not) while building up your joint farm

There are loads of co-op type games that work well on the Steam Deck.

Here’s a list of co-op games I have had a ton of fun with while playing with friends:

Deep Rock Galactic on lower difficulty is a great long term game you can pick up randomly and for 45min at a time. You can also adjust the difficulty between each run depending on mood and join random lobbies pretty easily. Rock and stone.

Valheim is a good Minecrafty option that’s entirely self-driven and has a chill vibe. If you love Vikings, you’ll love this game

Portal 2 has an amazing co-op experience, but it’s pretty short. Absolutely worth it though.

Phasmophobia if you’re into horror movie style gameplay and goofing off despite a ghost scaring the shit out of you

Factorio (or Cracktorio) if you like building things and watching them go brrrrr