Not if your apps run on Windows only.
ElevenNotes
KeePass, no sync need when used with KeePassium and WebDAV.
Transmission and then your normal *arr stack.
All three. Alpine (read-only from RAM) is the perfect OS for any RPi. Alpine in a VM is a perfect OS with native support for all hypervisors and drivers available from the start, and as a container base layer its simply one of the best OS out there. I run all my bare metal nodes with Alpine from USB (read-only from RAM). You setup a USB stick, plug it in, boot from it, done. You can setup the OS with your keys and everything, take the USB stick, simply copy the contents (its FAT32) and put it on another stick and plug that into another server and boom, OS ready, no installation required.
Disclaimer: All my bare metal nodes are for containers, the OS has nothing installed, so read-only from RAM is IMHO the best option to do so, unless you want PXE.
Many issues like?
You wrote a guide on how to install and use a Linux distro but you can’t install another distro. Isn’t that a little bit of a contradiction, same with the statement “with as little bloat as possible”, that’s exactly what Alpine is made for. Are you sure you should give other people advice?
Go Alpine, hardened from the start (almost).
I only use Alpine on Pis so I'm interested to hear why any Debian at all?
Unifi, built in payments via paypal and more.
Intel NUC or any other NUC for compute and a Synology NAS for storage (RAID6, so at least 4 HDD) and then please follow the 3-2-1-1-0 backup rule.
You don't need MACVLAN. Just move the synology ports to another range and then run NPM on :443.