I had a play on the demo this evening, probably about 1hr 30 for the full match. I enjoyed playing it, and I think you've got the base gameplay loop working nicely.
There were a few quirks with the AI opponent getting its soldiers stuck in furniture, and repeatedly trying to reposition them until out of energy, and a few times where I struggled with positioning on top of something (instead of inside/under), but essentially no game-stopping bugs.
I was playing on Linux Mint - I didn't look whether it's Linux native or running through Proton, but it runs nicely regardless.
Without a campaign, it likely limits the replayability a bit - but the general gameplay itself is fun, and a great position to be in for developing things further, in whatever direction you want to go.
Also, just to note a campaign doesn't need to be all cutscenes and gripping plot and voice acting and drama - a set of different maps that follow in an order, starting easier and getting harder (or introducing new units or map features on each level) would do the job just fine. Also, some people won't care about single player campaign things at all - so please don't take my personal opinion as the opinion of everyone :)
Anyway, it was good fun to play. I'll put it on my wishlist, and I wish you good luck with the launch and ongoing development :)
I recommend that you do not touch the diaper.