@GregorTacTac If you use containers you can map something like 8080 on the host to 80 in the container. Generally it's recommended to have a reverse proxy listening on 80 and 443 with all your individual applications on localhost only high ports.
Bitwarden has its own script to manage the containers. It’s not your typical self hosted app docker installation. What OP is looking for is easily accessible in their FAQ section of the documentation.
Q: How do I use custom server ports?
A: To use custom ports, instead of 80 and 443, edit the http_port= and https_port= values in ./bwdata/config.yml and run ./bitwarden.sh rebuild to rebuild your server assets.
Check that the custom port values have been proliferated to ./bwdata/env/global.override.env.
80 and 443 are the standard ports for webpages (http and https respectively). Lot of selfhosted software with web-based frontends will therefore try to use them.
You can change the ports for the bitwarden container to whatever you like, but the "proper" way to set up multiple services with web-based interfaces like this, is to use a reverse proxy to make them all accessible via these two standard ports. (Caddy is popular for this)
You can then access them using their respective subdomains or subpaths.
With vaultwarden it's very easy, just change the port map in the docker compose file on the host side. No idea how to do it with the official server stack.
Unfortunately, I’m not familiar with installing Bitwarden so I can only offer general advice.
Port conflicts happen at runtime, not when software is installed. In general, you should be able to install as much software as you’d like that all relies on port 443 but only run one at a time.
If you’re seeing port conflicts when installing Bitwarden, then I suspect that something is starting the app after the install is done. If this is right, then maybe you can disable the automatic start. Or maybe you can ignore the error at install time, then configure the app, then start it.