One great example of Spring RTS being used in a game is Beyond All Reasons, A Open Source RTS: https://www.beyondallreason.info

> All units and projectiles are simulated in real-time. The game offers fully simulated projectile ballistics, explosion physics and terrain deformation.

> The shape of every battlefield in-game imposes which strategies work and which units are effective. No two maps will play the same. Radar cannot penetrate mountains and nuclear warfare will physically alter the terrain.

Unexpectedly fun game.

Also, see:

* Glest http://glest.org/en/index.php which is modded by editing config files. There are lots of mods that add “factions” to the base game, as well as mods that are standalone games.

* 0ad https://play0ad.com/

OpenRA is another open engine!

Spring engine games do tend to end up feeling like TA which is fine if that's your thing, but I think the mainstream RTS audience these days expects SCII.