To me, multiplayer games are generally just a way to waste some spare time. I don't even mean that in a bad way or anything, I just play a few rounds of Mario Kart, Splatoon, Overwatch or League of Legends whenever I have some free time and don't want to get invested in something. They're the same as mobile and gacha games in that regard, I don't consider them bad, I just play them in a different way than I do single player games. I don't care about winning or losing either. It's just an enjoyable way to spend some time for me but I couldn't really tell you what I have done, if you asked me 30 minutes later.
I play singleplayer games when I really want to play something. I get invested in the story, gameplay and mechanics, and play just that one game for days or weeks, or however long it takes to complete the story and whatever sidecontent I feel like doing.
Normally, the downside to this is that I sometimes only play 3-5 games a year, Obviously Covid times were great as I got a lot more free time and I got to play as much as 25-30 long ass singleplayer games a year, though that has dialed back now.