I just did something sort of like what you are doing and after a few hiccups, it’s working great. My Synology just couldn’t handle transcoding with docker containers running in the background.
Couple differences from your plan: I chose a N100 over the N150 because it used less power and I wasn’t loading up CPU dependent tasks on the thing. The N150 is about 30% faster if memory serves, but draws more power. Second, do you really need a second m.2 SSD BTRFS volume? Your Synology is perfectly capable of being the file storage. I’d personally spend the money you’d save buying a smaller N150 device on a tasty drive to expand the existing capacity then start a second pool from scratch.
Finally, I wouldn’t worry about converting media unless you are seriously pinched for space. Every time you do, you lose quality.
Absolutely no good will come of this psyops group targeting Americans.
This isn’t a genie that can return to a bottle. This is everything Snowden warned the world about, supercharged and networked and only available to the administration currently in charge.