I have a 43" UJ6300 LG UHD TV, and a 150Mbps fiber circuit from Telus. It works very well, and I am satisfied with most features and picture quality. My one complaint may be a slightly dimmer overall picture to comparable TV's.
Probably because I was too lazy to thoroughly read the manual I did not fully understand the meaning of all of the features. I purchased a Roku Streaming Stick 4K+, and noticed an immediate improvement in picture quality. The Roku Stick I bought was mostly to enjoy sports subscriptions which were unavailable on WebOS.
I noticed that my Roku Stick immediately switches my "Picture Mode" to "HDR Effect" on my LG UJ6300. I falsely thought HDR Effect was just that, an effect, not actual HDR. I noticed my picture quality was improved even when the Roku Stick was turned off, which seemed impossible. Then I realized my TV was still set to HDR Effect, and that is what is improving picture quality. HDR Effect I believe is HDR10, which my Roku Stick uses. Roku also supports HDR10+ and Dolby Vision programming.
I learned that HDR Effect is by far the best setting for most programs broadcast today, as HDR10 has as far as I can see become the de facto standard for High Dynamic Range TV's. Try watching golf, football, baseball, it all looks best on HDR Effect.