Philip

How powerful should my hardware be?

I think 512mb ram is probably a bit too low. There is a risk for the pc to crash at some point. I think 1 GB+ should be fine.

Which ports do I need opened to operate a lemmy instance for my personal use (i’m only going to be connecting from home)?

To avoid opening ports you can use Cloudflare tunnel as you mentioned.

Only other option is probably renting a cheap vps. Here is a cheap vps options for 2.5$

If you have the ability then self hosting is the best option

Otherwise I think instances with less users and content will be quicker, but then the all feed will probably be smaller.

I will also recommend my own instance endlesstalk.org. It is very small(10 users) and the server is located in Germany. Hopefully that is close to where you live, so the latency is low.