What were your thoughts on the c715 and the c815? Apart from the OnePlus they are the other options which you can consider. Samsung has the TUE60A as well.
I had the 715 and 815 side by side and there is a difference when playing the same content on similar settings.
1. The brightness level is far better in the 815
2. Color reproduction is about 25% better in the 815
3. Upscaling wise also I saw there was a difference between them. Although on paper they are the same notice a slight difference where the 815 performed better.
4. The MEMC I could not test completely as neither the store nor I had any proper content to test with.
5. Gaming performance I still have to test have spoken with the salesperson and might do that test if possible via a ps4 Pro.
6. Software was something I couldnt test as such. Basic stuff worked fine, no lag using voice commands. It aint the premium tier so its not exactly snappy but voice worked pretty well. Other app launching, booting, etc seemed fine. (But in a short while cannot make a conclusion, long daily run will only tell)
Overall the 815 is better than the 715 but there isnt a huge difference and this is something noticable when kept side by side. Sound is an obvious difference as one comes with an additional soundbar. But the c715 sound is pretty loud. But I believe a soundbar would be required if you are looking for that perfect sound with tv experience.
C715 is about 6k more and can be a good buy if the oneplus doesn't pan out. I know im comparing a qled to a led uhd panel but fingers crossed. But if the oneplus does perform well in terms of pq then I think will go for that as TCL can be buggy as you mentioned and Oneplus does have a vetter reputation is terms of its community and software bug resolution.
TUE60A is a 6 series Samsung. The specs upon asking have yet to be received from Samsung as their specs mentioned on the site are completely misleading. So havent put in list yet.