Looking for recommendations as per topic title.

The premise is this: I work and will soon study at home, sitting at the computer. This sometimes requires my full attention and fullscreen software, but much of the time I can work just as well with the software occupying 50-75% of the screen (divided vertically), leaving the rest unoccupied. I'm looking for games that I can fit in that space, running in the background, but overlapping with the work software is OK if the game can be paused or auto-pauses while I switch away from it.

Because of this hopping between windows, the game(s) should be the sort that can be left to its own devices without my character(s) dying while I'm not paying attention, and ideally have a plot that is superficial, easy to follow or meaningless. To give you an idea, I currently play Inscryption, FTL: Faster Than Light and Darkest Dungeon in this way, and used to play Sunless Sea as well (but that was too captivating). If you have any suggestions or recommendations, here's your chance.

I know what some of you are thinking, and the thing is that clients pay for work that I deliver rather than the time I spend doing it, so it's no skin off their back - plus I might be more productive in tedious projects if I get micro-breaks without leaving the desk. In addition, while I can try to play games in the evening or over the weekend, that's easier said than done due to family considerations and other pastimes. In hell and adult life, this is all you get.

You might look into incremental games. I've been playing Swarm Simulator lately, and aside from a few parts (the early game and right after an ascension), you really only need to interact with the game occasionally. If you just leave the game in the background (or even if you close it, at least in the case of Swarm Simulator), your swarm will continue to function, producing more meat and larvae, without your interaction, but occasionally interacting with the game will, of course, allow you to get upgrades to purchase even more.

So, Into the Breach, for starters.

And Steamworld Heist, I'd say.

There's also forum mafia games, and they may need a replacement player very soon. You should have a look at that.

Heroes of Might & Magic (and similar games).
I'm not sure if all of them can be played in windowed mode, but at least that's not a problem for the first HoMM games since they run on DOSbox.

I will use literally any valid possibility to recommend Any Spiderweb Software game. They're very much Ultima inspired CRPGs, and most of them have no time constraints, and all of them can be windowed.

Any Space Empires game can have quite long legs as well.

Fez is lackadaisical, and while some puzzles have timing to them, the majority of the world is your pace to take.

Same with Any Myst Game.

Two of the games I played to death in similar situation are Into the Breach (as recomended by Telika) and Battle for Wesnoth.
If you are into arcade or casual games, Plants vs Zombies (may have issues with window size) and SuperCrateBox get my vote.

Fates of Ort - should be something you would like, combat kinda reminds me of Superhot (just kinda), times flies when you move, so you can pause in any moment of battle. It's also more interesting than most turn based games (at least IMO). It has simple graphics, so should be fine for window mode.
Loop Hero - maybe too engaging, I dont know, didn't play it a lot, but it pauses the game during alt-tab
Point&click games maybe? If you like them. Some indie examples: Thimbleweed Park, Unavowed or lighter Chuchel.
Battle Brothers - maybe too complex to do break every 5 min
Peglin - should be fine
Yes, Your Grace

DROD is as slow or fast paced as your key presses are and works very well windowed. If you like that sort of puzzle game it's a particularly deep example, with every sequel adding new mechanics to the mix.

I'd say any 4X game, but maybe that's too heady for what you're asking. Maybe try Civ 4 and just cheat with the world editor and give yourself maximum technology and see how long it takes to roll over everyone.

Could also try Wasteland 1, but I haven't played enough beyond a very superficial boot up before I got stuck on some things. EDIT: You can't Alt+Esc or Alt+Tab for whatever reason, but you can put it in windowed mode by pressing Alt+Enter. Unfortunately, it seems to lock you to that window and the only way to take it off is to just quit, so maybe not the best thing if you want to stay productive.

There's also Desktop Dungeon, with its short but tricky minesweeper-like puzzles.

West of Loathing runs windowed. A fantasy-western RPG (skeletons AND six-shooters!) Turn-based, hilarious, and surprisingly deep.

Disciples 2, if you're into dark fantasy settings with Heroes of Might & Magic-like gameplay.

Gwent