This is going to sound snobby, but until you’ve played metal gear I don’t think you’ve experienced the pinnacle of stealth. That series basically defined (access arguably perfected) the third person stealth action genre.
If you don’t want to play them all, I highly recommend metal gear solid 3 and V. But the “demo” ground zeroes game is a great way to get a feel for the series in a more contained experience
Runner ups in my mind that others mentioned:
- Splinter cell
- Thief
- Deus ex (you can choose stealth in this game but it isn’t specifically a stealth game imo)
- Dishonored (superb)
- Prey (essentially dishonored meets system shock)
You gotta go grab some metal gear, though. Oh how I wish I could experience those games for the first time again.
And like regular DND, positioning is really important. Use the environment to your advantage: block line of sight, have the high ground, use spells that have an AOE to drive enemies where you want them to be.
If you go charging into the middle of the open room surrounded by baddies you’re probably gonna get wrecked.