KDE Connect has been mentioned before. You can supplement this and other tools by using a VPN so that both endpoints can see each other even if the underlying network does not allow this. My preferred solutions are Tailscale (managed, cloud-based) or Headscale (for self-hosting).
Well, you have Finland in the north-east, Ireland in the north-west, and every land border faces a Euro-zone country. Few other countries can claim the latter.
If at all, you want to use Gentoo’s ebuild system, which can be seen as some kind of superset of PKGBUILDs. I guess one could write a Python script that “dumbs down” ebuild scripts to PKGBUILDs for simple packages (excluding complex stuff like kernel, KDE, …). The main challenge, as pointed to before, would be maintaining a table mapping package names between distributions in order to get the dependencies right.
The “C” in the progress bar is alternating between “c” and “C” to give the impression of munching.
There is some information missing in the problem description. For example, if you close the lid, does the computer suspend/sleep/hibernate? It may be that when the computer sleeps something “breaks” or it may be that the act of physically closing/opening the lid has an effect (e.g. because the WiFi antenna is embedded in the display frame).
Some time ago I had a similar problem with Tailscale and sleeping. When Tailscale initializes itself (at boot), it has to interact with another service to communicate which DNS servers have become available (e.g. 100.100.100.100). Several implementations of such services exist (resolvconf, openresolv), in my case systemd-resolved. During normal operation, resolvectl status (if using systemd-resolved) shows which DNS servers and which search domains are configured for each network interface such as tailscale0. Now, there is a bug (or feature) that systemd-resolved “forgets” the DNS configuration it got from Tailscale when the computer is put to sleep. So, when the computer wakes up, name resolution via Tailscale no longer works, giving you the impression that Tailscale itself is not working, although Tailscale’s low-level functions are still operational.
My “solution” was to write a small script that gets executed when the computer wakes up which sets again DNS server and search domain for network device tailscale0.
ArchLinux’s pacman with ILoveCandy option enabled.
There was choice, but not enough volunteers: https://www.debian.org/ports/kfreebsd-gnu/
If you do not trust Tailscale as a company, here is an open source re-implementation of the server called headscale. Some/all clients are open source as well. So, you can review all components yourself or pay for a professional third-party review. Otherwise, if you take a binary blob from any origin, including Tailscale, and have it run with privileges on your server, there are few limits on what this blob can do. Yes, backdoors are technically possible, but probably bad for Tailscale’s business if that ever came to light.