Are all these changes required to update Node from 18 to 22 or is the one-line change in package.json enough?

tbh I haven't even tried to bump the node engine alone.
anyway it's just dependency updates, I don't see why one wouldn't want to do those unless they cause incompatibilities which I haven't found

Ah, yeah, updating dependencies is a good idea generally. I was just asking more out of curiosity since I'm not a web developer. I only updated the node version in package.json in my fork to make the smallest change required in order to isolate any complications and it appears to work. Both the deployments of my fork and example of my instance shown below look good to me.

in hindsight one could argue that with all the supply chain attacks plaguing npm packages maybe your minimal change is better, anyway let's see what the maintainer thinks

Is the maintainer still active or do we have to do a fork of the project ?

Is the maintainer still active or do we have to do a fork of the project ?

Based on the commits to main, there was a commit co-authored by the maintainer on May 7th. So, I'd say it's still maintained.

I forked the repository in order to deploy your own instance, which I would recommend. If you do that, you can update the node version in package.json to avoid the deprecation on Monday, September 1st.