For my phone (almost 7 years old), a thin needle to scrape out all the dust is sufficient. Pressurized air also helps.

Me, a physics educator: “Interesting!” takes note

I am using Librera Reader. Make sure to install the F-Droid version (Librera FD) without Google Play services.

It is primarily an ebook reader that supports a variety of formats, but it is also an excellent PDF viewer. Significantly more feature-rich than any other FOSS PDF viewer for Android that I have found.

Windows is in the wrong, not Linux.

reg.exe add HKLM\SYSTEM\CurrentControlSet\Control\TimeZoneInformation /v RealTimeIsUniversal /t REG_DWORD /d 1 /f

That does not sound plausible to me. Typically, your own computer would be behind a router that is either doing NAT or has a firewall (probably the former). Any incoming traffic would be directed to the router without any chance of reaching your computer. Whatever you saw was either outgoing traffic or incoming traffic in response to connections initiated by your own computer.

Connection attempts from the FBI? Could you specify that a bit further?

home assistant, freshrss (and a few related services such as rss-bridge), nitter and piped. I tried to host libregrammar, but ran out of memory.