Two more generic things you could try:

1. Lower the Discord voice codec quality, just to see if it changes anything.

2. Uninstall your GPU Drivers with DDU and reinstall them.

Take a look at SULFUR, could be what you are looking for. I think there is a demo too.

Wolfenstein: The New Order

I played a LOT of singleplayer FPS and this is one of the best in the genre. Great gunplay, fantastic soundtrack, good story.

For people unfamiliar with their games: Their first one “Gravity Bone” is free on steam. It is super short and almost 20 years old, but it shows off their style and humor very well. Loved their games ever since.

Money.

How about Assassin’s Creed Origins? It takes place in ancient Egypt. Don’t know if it is any good though.

Probably Mario 64, just because it was so revolutionary at the time.

No! If I am stuck in modern slavery, then the AI is too!

No one mentioned it yet, so:

Die Hard Trilogy

Older: King’s Bounty

Newer: Songs of Conquest

Edit: Never mind, I thought you meant Heroes of Might and Magic.

Edit2: Maybe Legend of Grimrock? There is also a sequel.

Since the Wolfenstein games were already mentioned: The Saboteur

It aged quite a bit, but there are some nice mods to make it look and handle a bit better on Nexus Mods.

Tactical Breach Wizards

It is similar to Into the Breach in some ways.

Die Hard Trilogy

Last time I played CSS was in 2018, so I can’t really answer that. But according to SteamDB there are currently 11000 players.

I have a lot more hours on Counter-Strike Source than that, but that was before Steam started counting hours. I also played a ton of Sims 2 and 3.

A ton of Darktide.

Death Stranding

Oh, that must be exciting and nerve wrecking at the same time, seeing your characters come to life. How do you convey what you imagine the characters to sound and act like?

Die Hard Trilogy

That is not really true. You can ignore the persons you meet completely and play the whole game on your own. Also, you can only interact through audio effects and a small proximity effect, to charge your scarve. They are more like a ghost, playing alongside you.