I’m finding it a little hard to follow your description sorry, but couldn’t you do something like: Outside Internet -> Modem -> Router -> network switch -> devices?
Sounds like you just might need a network switch with more ports.
And I feel like it’s not a good idea to have a modem directly attached to the pc directly unless you’re using it as a router?
I’ve enjoyed the Synology OS personally. I’m messing with a custom build with spare parts though.
IMO I think symbology is a good point of entry. I haven’t tried HexOS but it might be pretty good down the line for a no fuss system.
Edit: Sorry just realized the comment was about UGreen. Have my 2 cents about synology anyway. 😇
This is not the flex you think it is
Give me more reasons to not visit!
IMO I feel like what you’re doing is the best way to learn.