I have used LMS for years, going back to around 6.2.0 whenever that came out. It can be installed on a PC, Mac, Nas's and raspberry Pi's, with my Squeezebox classic/touches.
There are other DNLA servers, but I've only had extensive use of LMS as it's always just worked, is snappy in use (as long as the hardware is capable enough - only time I was slightly frustrated with it when using a NAS with slow 300mhz single core CPU, scanning was slow, navigation was a bit sluggish but once selected an album and playing it was ok, as long as not copying to the NAS at the same time) well supported and been out for a long while. Also need IP reservation, I've had the SB not find the server as dynamic IP has changed.
NAS's have their own DLNA service, but I haven't been impressed with the one in the Synology. It's basic, non configurable, slow, not even worth using. LMS on my quad core realtek Synology was plenty fast, but supported was dropped at 8.2.0 Now using a pi5, 4GB RAM, and having LMS 9.0.0
If the wiim music scanner isn't good enough I'd just look elseware, you're just trying to flog a dead horse and get frustrated about it's foibles- you sell the wiim out of frustration getting rid of a good product just because of a beta service- where theres alternative options.
Keep the wiim but look into a stable music scanning service.
As mentioned LMS won't work with Wiim home app, but I've used the UPNP plugin, so it should work with Wiim app?
I don't own a Wiim myself.