I don’t think its too bad, but it probably depends a lot on a lot of factors.
Since I first started my hardware got a lot stronger, and nextcloud, php, and mariadb have all improved and so my experience has gotten pretty decent.
Remember though, there’s a ton of biases here, so I could be wrong…
I’ve found the biggest thing isn’t any real resource. My instance runs on a core 2 duo with 4GB of RAM, and I really try to get it to waste memory and barely fill the 4GB.
The thing is your instance will be blasted by all the other instances you subscribe to. If you subscribe to too many big communities you might find you’re locked out during peak times, but it should be just fine as long as you’re not crazy with follows like I am lol