I played a few games that were just really mediocre.

• Warhammer 40k: Inquisitor was a super boring ARPG and I couldn't put in more than a few hours. The levels were super short and just corridors.
• Pathfinder: Kingmaker started out ok, but was just far too long, terribly paced, and the last third was a complete slog. This was probably the one I'd call a "stinker" the most.
• Crisis Core Remake (FF7 spin off) had a boring story and lame characters. The bulk of the "content" were 300 side missions that were usually less than five minutes long in one of like six stages. I picked it up after I enjoyed the FF7 Remake far more than I thought, but this game adds nothing to the overall story. To be fair to the game though, I did complete all 300 side stories, because from time to time I like a mindless grind.
• I'm continuing my four-year-old save of Octopath Traveler, where I got a third or so in. I dunno if it's the Steam Deck, but there's just tons of aliasing, shifting sprites and flickering, it just looks bad, and the detailed enemy sprites were the only thing I really liked about the game in the first place. Combat is also a slog at times, so I don't know if I have it in me to finish the game.