Got the same problem.
My Synology NAS and other PC's with shares do not show up in "Network". Thou typing it's explicit name or IP-adres, gives me access.
It does show as a "Media device", but not for file sharing.
Same for my "old" pc, sharing a couple of directories on Windows 10 pro
They do show up in "other devices", but that opens their webpage or give information, not the shares.
All the mentioned services are up and running. And everything worked fine in 23h2
OS: Windows 11 Pro 24h2
NAS running SMB sharing
Win 10 Pro PC's, windows file sharing
Problem solved:
Had to enable "server signing" on my Synology NAS. It was already user + password protected, but this option put my NAS back on the "Network".
Also had to tick "allow other network users to connect through this computer's internet connection"
Windows 10 Pro pc's are back on "Network", so is my NAS.