A hard drive in a PO Box; data encrypted. Retrieve it occasionally to sync it with your local storage.

Are there any truly FOSS networking options?

PFSense falls into this category for routers. Netgate makes hardware specifically for it, but you don’t have to buy anything from them to use PFSense. I only mention them because their hardware is good and you can buy anything from a normal home router to enterprise level gear.

I had to sign in with my ubiquiti account first before I could make a local account

I used to be pretty into ubiquiti, but this requirement really put me off. I have no desire to do anything ‘cloud’ with my router. This requirement sent me elsewhere and I sold off all my ubiquiti equipment.

TruNAS … What alternatives are there?

TruNAS has a community edition, so you could start there. Other alternatives are a standard Debian install, use mdadm to setup RAID, then setup a network share in the OS, etc.

I had to set the power profile in Linux to ‘power saver’ to keep the fans from going nuts. The biggest change is the CPU doesn’t boost, but for my purposes that is ok and the quiet is better.

Love to see they are working on making this better.

I default to exFAT for flash drives. Every OS can use it out of the box, so it is the obvious choice.