hmmmmmm let me see.

Web based? lets do web based.

Do something simple like a basic crud app on web api format:
Do it with full authorization and authentication.
Start hard. Do it with pure golang using NOTHING but the std libraries.
Now, do it in a magic mvc framework like Rails or Laravel
Now do it on dotnet core
Now do it in django rest.

Watch the differences in all of them, sell your soul to something and now do it in Clojure. If you do it on a Scheme dialect or on Common Lisp my CMS admin will suck your whatever you have. Dude seems to be pretty good at it, we are trying to keep him from pulling tricks on the street but he insists.

Then add a React client with Typescript to get them basic ass endpoints to display nicely.

It should give you a fuckload of perspective amongst the different tools and way we do things and might make you appreciate the differences in paradigms required(pro points for doing modular in c# dotnetcore using different classlibs for the major points of the application using some crazy pattern like the mediator pattern)

I would hire a mfker that throws all this shit at me on a portfolio on the spot.