Sorry, like I said, don't know anything about RSS feeds so I don't understand the process of how you would build and serve such a site. I honestly have no idea how to serve RSS feeds or even what they are! But if you are just creating directories of files for people to click on, that is very straightforward.
RSS feed is just an XML file, linking to feed items. In podcasting's case, it links to the audio files.
Had quick look at the link you posted, appears to just be a basic web server. Why do you think it would be better than MAMP? I don't understand the part about "not worrying about machines on other networks spoofing my machine and attracting connection attempts from my iOS devices". If you want to serve using https, MAMP can do that and so can a direct install of Apache. You can generate your own SSL certificates, but they don't behave quite the same as a "real" https internet site with something such as a domain-validated cert.
The concern scenario is I have my iPhone's Podcasts.app subscribed to feeds.xml on
https://192.168.10.1:8050/ and downloading anything it finds at that address. The phone is taken to another location and a malicious server configured similarly will have that file auto-downloaded in the background.
Podcasts'app has a significant vulnerability to malformed RSS feeds, and loads them in the background, even if you're not actually subscribed to those feeds on the device itself, by the mere presence of files from that feed (synced via iTunes, for example). So if the feed is malformed, you can end up with the app in crash-loops, for example.
I literally explained to MAMP that I wanted to serve with https and use a self-signed certificate, and their support people said "it won't be suitable for your purpose" and closed the ticket. I re-opened it and asked them to explain further, and they were similarly taciturn with "it's designed for local testing only" and closed te ticket again.
Simple Web Server looks like it might be an option as well:
Create local web servers in just a few clicks with an easy-to-use interface. Download for Windows or macOS.
simplewebserver.org
They could use a better logo, but it seems to do all the things.