Hi @fcstoffel
A lot of questions... Lets see if I can shed some light here.
In order to run Funkwhale in a way supported by us you either need a Linux VPS/Root Server with some Python interpreter and the ability to install Redis and Postgres or a system where you can run docker workloads.
A shared webspace is likely not an option, while it would be theoretically possible I doubt there is a provider offering what is required to run Funkwhale. https://uberspace.de might be one.
In case you already are into running your own services, this is probably helpful. In case you are not, its likely not.
You can rent a cheap VPS and run our quick install script to get Funkwhale up and running. Another easier way to get up and running is YunoHost or HomelabOS, both linked in our docs: https://docs.funkwhale.audio/develop/administrator_documentation/installation_docs/third_party.html (please note, those are not supported by us and if you need help, its better to talk to the packagers first).
If you want to avoid running Funkwhale yourself, there are managed services available, eg https://weingaertner-it.de/index.php/produkt-kategorie/funkwhale-hosting/
If you are asking for technical requirements, this highly depends. People run Funkwhale on a raspberryPi, so you can probably get away with a kinda weak CPU and 2 GB of memory already. An important thing to consider is the storage, music collections might grow pretty big over time. If you plan to have a massive amount of users on your instance, you should be able to scale it up accordingly.
I hope this helps, if you have more questions, let us know!