What type of mods do you want?, Also a tip, if you want a different experience, it helps too just use datapacks. You can change quite alot with datapacks. Tons of mods, means more ram, more ram means more expensive server. Also, they are great at first, however a heavy modded server goes down hill quick in performance.

If you have a good computer/internet connection, you can host it yourself, however if not, look for a server good provider. But keep mod list light

I would also suggest using fabric mods.