I did port forwarding in 2010 for a Minecraft server. Basically every router supports it.
It wasn't meaningfully more difficult than setting up the server.
Most isps, you can’t do that anymore as you no longer have a publically reachable IPv4 address. It moved the ‘just configure your router’ part to their equipment, as they now use CGNAT.
It’s gotten much worse.
You can't do that with CGNAT.