It seems that the best for this project is to sell it to some poker company trying to capture Poland's market.

If you have time (like, years) to develop the project, among the ideas you've already shared (a store for chips/accessories), you could turn it into the tips&tricks website, news, and everything else around poker (in Poland, so without direct advertisement of poker clubs to avoid any restrictions on you).

We were using K8s on DigitalOcean.

It is a great tool, but a little bit overly complicated when you have just a couple servers. :)

Now I'm using my own tool - #ptah . It uses Docker Swarm under the hood and is very opinionated (but reasonable) on how your cluster should work, saving you hours from being spent on configration.