Syncthing on my home server, synced with each device I use for notetaking, has been glorious so far. I wish Obsidian would offer Sync for a cheaper rate, because I’d pay if it felt like anything near the cost of actual sync and storage. But Obsidian’s cheapest tier is more expensive than my email hosting!
2TB is insanely small for a NAS. At that point, you could honestly just run a Pi 5 with M.2 HAT and a 2TB SSD for something like $200 total. Could always buy a second Pi for mirroring and even locate it in a friend or family member’s house for mirroring and backup.
I use a Pi 4 with 7 TB of external SSDs just fine at home. It also hosts a pi.hole ad blocking server, my 1TBish jellyfin music streaming collection, my network share for kodi, an always-on VPN for my phone and laptops, and a few other small services. I’m sure I could upgrade for better read/write speeds. But everything is performant enough as is, and it’s completely silent and fan-free in my living room by the router. Honestly for most services a Pi with a passive cooler will perform admirably.