i’d say start small. do the the webpage on some old hardware, maybe a wiki. content consumption things that would be uncomplicated for the group to adopt. avoid things that would mean managing accounts for other people early on. a wiki or some static page using something like modocs will be easy to run off a decent internet connection at the building. low bandwith usage and low traffic.

if your goal is to degoogle group, nextcloud could be helpful for the organisers. maybe if you have success on the simple sites you can get people on board with some hardware for a small nextcloud server. but dont plan on opening the next cloud up to the kids. thats a world of risk you don’t need to open up.

if you’ve already got something at home to run it on and want it easy to set up/maintain. take a look at mkdocs.