IDK if released as a "cloud edition" or native, but https://www.nintendo.de/Spiele/Nintendo-Switch-Spiele/It-Takes-Two-2265759.html is probably the best co-op game we ever played with my wife.
Other than that, some of our favourites (tried to sort by relevancy to your question):
- Children of Morta
- Overcooked 2
- Guns, Gore & Cannoli 2
- River City Girls
- Death Squared (not PvE, puzzle game but a great one)
- Snipperclips (ditto)
- Super Mario Bros U Deluxe
- Luigi's Mansion 3
- Pico Park (better with 4 players)
- Unrailed (maybe not very casual/easy though)
Other games that may not be your cup of tea but still:
- Mario Party games
- Warioware Get it Together
- Crawl
- TMNT: Shredder's Revenge
- Super One More Jump
- Out of Space
- Enter the Gungeon
- Marvel Ultimate Alliance 3
- Urban Flow
- Catherine Full Body (has a co-op mode)
Hahaha didn’t know this exists, Thanks I will!