minecraft server hosting is around everywhere, with budget of 50+/month, you can get pretty decent stuff.
first things in google after searching for "minecraft server hosting"
https://mcprohosting.com Only one i've had personal experience with, it works as far as I saw.
https://bisecthosting.com
https://ggservers.com
Rest I will not list for now, since search result claims "free server hosting" and there is no free cake on internet, especially GOOD cake, that your planned mod amounts would require.
For mod setup/config, you might want to test run it on your own computer first though but... up to you.
edit: If you want to build your own server, go for it... if you get the server as jar, you can run it on linux which is free.
Only problem with minecraft is, it's pretty much single core only so... better CPU might be necessary for that amount of mods.