Repterra is a promising upcoming real-time strategy game that has a demo available, and if you love the idea of facing hordes of dinosaurs it's one for you.
Set in a similar gameplay style to the likes of They Are Billions and Age of Darkness, with you building and expanding while also dealing with hordes that will come to try and destroy you in waves. So it's a bit of a mixture of classic RTS building with some tower defense. The demo as tested worked perfectly on Linux with Proton 9.0-4 and it's going to be worth keeping an eye on, as it's exactly the type of RTS I love to see more of.
You're not just building up walls to hide behind though, you'll also be building up your own little army of humans and dinos together - some dinos can even have a human jump on their back to unlock special extras. I just think it's neat to see.

Direct Link
A little rough around the edges since it's a demo of an unfinished game, but it shows a lot of promise that reminds me of the good classic RTS games I played endless hours of in my youth. Looking forward to seeing more of it but there's no release date being mentioned for the full game just yet.
Some Highlights (from Steam):
- Unique Breeding, Riding, and Taming mechanics.
- 5 Different factions with unique play-style focuses.
- Game modifying perks that can be chosen at load-out.
- Permanent unlockable points and shop (levels, perks, bonus features).
- Customizable hero units..
- Campaign mode.
- Extensive Survival mode with unlockables and meta progression.
- 100,000+ dinos running at a smooth 60fps.
- Dozens of different units, dinos, and buildings.
- Achievements and Steam Cloud.
- 4k High rez graphic in a timeless pre-rendered style.