recommendations to check if a point is in a map zone in webpage

I know there are already some posts asking about this topic, but i seek for recommendations.

Basically what I want to do is a webpage where the user picks a point from a map (haven't decided which one im going to use, i suppose it will be google), and check serverside if it is inside of some defined areas (possibly stored as geojson polygons).

I am pretty new to website development, i have some knowledge about C programming so my first thought was to look for something done in php (just for the similarities in the sintax). I found geoPHP which seems useful to reach my objetives but im not sure if it is really the best way to do this.

I am not afraid of learning other languajes, so what I am asking is if there are some optimal ways to do this. Also this geoPHP github repository was made quite a few years ago and im not sure if that could be problematic in some way...

I tried using this one fork of geoPHP https://github.com/sookoll/geoPHP (i got it from geoPHP point in polygon) because im not really sure how to install the GEOS package since im hosting my webpage in a provider with cpanel (and a modified one because as far as I could see there are very fewer options than others cpanels I've seen in videos).

Again, im just looking for recommendations, if i should keep going with this geoPHP fork, or maybe taking another way is better.