We loved our BV5, mainly for the reason you motioned re the picture. It just seems so natural; the colours are not hyper-real like new TVs. Plus, I think it was the best looking Beovision they made. (just my opinion)
You probably won’t need to add any other sources but I had an Amazon Fire TV connected using a similar adapter. I loaded KODI on the Fire TV and was able to play Music and Video from my PC and use Amazon Music and Prime films. I also dabbled adding Plex, but never took that much futher as KODI seemed better for me.
I had 4 Beolab Pentas connected. It was just a brilliant TV with amazing sound. I sold the BV5 to very good friends who kept saying they wanted it. They still use it and love it. I have the Pentas in storage as one began to play up.
It is great you still love yours
Stoobie