To all of you that tried to provide some advice for me - here is my experience with MWS after several attempts.
It seems that the problem stems from default versions of nodejs/npm in Ubuntu Server 24.04 LTS and Debian 12.11.
Their respective (default?) versions were node v18.19.1 (v18.19.0 in Debian) and npm 9.2.0. With these the installation process fails because the needed subdirs and files are not created/downloaded. The installation creates only two files (localhost_certs.sh, package.json) and then fails because it cannot find the needed files. (ChatGPT was, originally, pulling me away from the real problem… so I got completely off. It was enough to check what actually got downloaded…)
After I have manually upgraded nodejs/npm to latest version (LTS) and got nodejs v22.18.0, npm 10.9.3, the installation succeeded.
I have also tried Fedora Desktop 42, where the installation worked out of the box, with default versions of nodejs of 22.17.1, and npm as 10.9.2
The only thing I could not figure out was changing the listener from localhost to 0.0.0.0. But at least I could tunnel it via SSH, so I can now access my MWS over the network. This is great.
Thank you all who have shown interest in this topic.
AS