Enjoyable, low-stress, shorter games with a good story...

To the Moon?

Lego games
Though I don't know how long are those

Portal? 6 hours or so to beat the game(story). Endless fun :)

Payday 1 or 2

Ninja Gaiden

Limbo,bastion (if you won't use any idols)

For more adventure: Botanicula,broken sword
Machinarium could be a little hard(especially last part) so changing it with thomas was alone :)

You may want to take a look at The Cat Lady. Grea, great story

Goat Simulator. Short, low-stress, and it's granted you'll cry.

To the moon
Samorost 2
Machinarium
Aquaria
Bastion

Just checked your list fast so I am sure there are more in there.

If u like portal, Antichamber is a known candidate.
Bastion
The binding of Isaac
Cthulhu saves the world
Dust: An Elysian tale(has a casual diff which makes it story only easy)
FTL: Faster Than Light
The batman franchise is pretty short so u can take ur pick from any of those if u stick to the story and dont 100% it by pickin up drops.

I know you said you're avoiding 100+ hour RPGs, but I find it relaxing to wander around Skyrim with godmode on, just exploring. I see that you own it as well. Still, consider what I have to say.

Skyrim can be set up as baby's first open world rpg, where the only challenge is wrapping your head around all the mini-stories you uncover in the side quests. You can play legitimately, or use cheats to make the game as easy or as hard as you wish it to be.

The main quest itself is not that long, maybe 5 hours if you don't count leveling-up time. Cheating cuts that down even further.

Considering that you can pause it at any moment and save/reload at any point, and the game defaults to autosaving at every travel point, and there's several autosave slots that it uses in sequence, there's potentially zero checkpoint issues.

Sometimes I just roleplay a bit.

I will wander around with 100 Archery and a powerful non-flashy bow, hunting wild game. I'll skip the perks that break my immersion, like eagle eye. I crank up the grass density so everything looks lush and beautiful. I install a mod to eliminate the extreme ragdoll animations that arrows cause, as though you fired a cannon at your target.

I can 'acquire' a guard's uniform and hop on a horse and ride from town to town, looking for bandits and wolves to remove from my country's well-traveled roads. The people must be protected!

I can dress in non-combat clothing and be a merchant kingpin. I'll dress in trade-appropriate clothing while crafting potions, weapons and armor, and I'll enchant gear for profit. I'll avoid killing anything powerful during this, staying with the animals I need materials from that I believe a simple merchant would be able to kill. A companion serves as a bodyguard while I cower in the corner and down six gallons of healing potions. Dungeon running is completely out of the question unless I feel like exploring a little beyond a mere merchant's life.