Thank you megatronx for your constructive answer and useful advices. I will surely tweak a demo very soon with changes based on what you pointed.
Today I released the full version of Erdluitl on Itch.io and posted a small development log.
https://nabu.itch.io/erdluitl/devlog/668365/full-version-and-update-12
This version was mainly for stress testing (singleplayer and multiplayer), stability, some value adjustments and bug fixes. By "stress testing" I thought of the ability of the engine to handle bottleneck situations, but I also discovered that it can cover user interactions. In fact, some players will press buttons in ways you wouldn't expect and cause bugs the dev didn't imagine (like pressing a thousand time on two buttons before action complete, to see what happens...).
The first campaign has also been completed and tested.
Come and try the game !