Your requirement for a mobile iOS app makes it harder so I’ll go non-free software with my suggestion: Tap Forms. Offline first, iCloud sync, macOS and iOS apps. But no Android or Windows apps.
If you wanna keep it self-hosted, these services need an internet connection anyway, even Airtable. Just go with a Web based one that has good mobile layout.
hoppy.network seems like a very expensive Wireguard provider ($8/month for 1TB@100mbit). For that purpose one can spend half that for a VPS with gigabit speeds, even a quarter that during promotions. That provides the same services plus whatever else you can fit to it. What am I missing that they provide?
Put.io only has torrents, though. There’s also premiumize.me which has torrents, Usenet, and some DDL. It has been a bit of hit and miss for DDL, though.
In case nginx does not work out for you, you can opt for more generic reverse proxies. frp is my favorite one: https://github.com/fatedier/frp
I have self-hosted my own emails many times. Up to having three SMTP servers with failsafe option at DNS.
It’s super nice, but I would never self-host SMTP again. It’s a nightmare. I had to email or open a ticket at most ISPs despite my clean IPs. Most ISPs simply blacklist all IPs unless they are major email providers already.
My advice is go for it but let SMTP be handled by who will deal with these frustrations. MXroute is a great choice and it’s cheap.
I use https://github.com/bastienwirtz/homer because it is dead simple to configure, and I protect it with HTTP auth at the reverse proxy level.
The development never stalled and the app has already improved. You need to access a new TestFlight link. See their latest post: https://lemmy.ml/post/1550828
Look at the PDF carefully before sharing it. Most academic publishers put a timestamp on it that reveals who downloaded it, at least at institution level. Sometimes this is even embedded as metadata. If the PDF says anywhere “author personal copy”, please don’t share it on the author’s behalf.
This is mostly to avoid getting them into trouble.
Otherwise, go and share, authors love it!