What’s the main advantage of having a huge server, compared to an average Synology NAS for example?
You can do much more things much more efficient. If you’re out for a NAS, get a DiskStation, even the simple ones with 2 slots are absolutely fine. Get a Seagate Exos X20 with 20 terabyte of storage, or 2 of them for a RAID, and you’re good to go. Or build something yourself with an external case and a Raspberry Pi.
Why should I get a homelab instead of a regular NAS?
Right now I’m using Docker and I’m hosting an ActivityPub server and a front-end (client) for it, a web server, a Minetest gaming server, a web Git platform and a custom application for some specific logging i’m doing. The same server also runs a reverse proxy and a Docker management platform. All on one older SOC machine with a recycled 1TB SSD. I couldn’t do this with just a NAS, even if the DiskStations are (were?) very “hackable”.
If you want to do anything more than just providing files via network, build a custom setup that fits your needs.