New to Jellyfin and need some advice

[Hollywood]

But I generally recommend using some external smart tv box over any TVs built in smart OS.

I like my Chromecast with Google TV 4K.  A lot of people like their Rokus.  I would get the Roku Ultra if I were to get one.

My library is mostly DVD to MKV rips. I use the LG smart app to access Jellyfin. It seems like the movies look better played from my 4k BlueRay player.

Would a 4k Roku "upscale" content to look better on the TV (then the TV smart app)? The prices are reasonable enough if there is a significant picture quality difference.

Thanks.