I made a blog about this. Make sure to follow it via RSS too ;)
https://joelchrono.xyz/blog/newsboat-queries-and-freshrss-scraping/
Stick to local stuff, no need to open ports at all. I got myself a Raspberry Pi and I just have it next to my router.
Once I felt like using it outside my network, instead of opening ports and doing complicated stuff that didn’t work cuz I am behind a Nat, I just used Tailscale instead, it’s a private VPN that is free for a limited amount of devices (like 10 or more I think so it’s fine for you and family). It’s the best easiest thing ever
FreshRSS is what I use and I can create my own feeds using X path, it’s kinda great but too much to explain. I wrote a blog about it.
https://joelchrono.xyz/blog/newsboat-queries-and-freshrss-scraping/
To be honest you can get Cave Story for free already since it’s open source and in many distro repos. Also I think the publishers kinda ripped off the original creator so the guy who actually put the work making this masterpiece isn’t getting anything