In my honest opinion, and it is purely my personal OPINION and nothing more, is that I wouldn't bother. Advantages to 4K ultra hd are true 4K resolution, HDR/dolby vision, better sound with Atmos and lossless audio formats and some of the better UHD players upscale lower resolutions better.
Now for my debbie downer view on it lol. 4K vs 1080p blu ray, meh, many people really can't tell the difference at normal distances and standard tv sizes. And your tv will upscale it to 4K anyway. So it kind of depends on how well your tv does upscaling. That tv probably isn't bad. Probably not the greatest, but most likely not the worst. From what I have seen they get decent reviews. All my 4K movies came with standard blu ray versions too. I have looked at both for every movie and I can't tell the difference in resolution between them. Both look great. The only differences I see is the 4K disks have HDR which changes the colors, how bright and how dark the picture gets. Turn off HDR and honestly the only difference I can see is the 4K ones are a little darker over all.
Which brings us to HDR. The jury still seems to be out on that. Some like it, some don't, some could care less. From what I have seen it really depends on what you are watching and what you are watching it on. On my older LCD tv I wasn't all that impressed. On my new OLED tv it like it a bit more. And dolby vision is even better. Which your tv doesn't have. Could I live without it? For sure, no question about it. It is not something I would pay extra money for or go out of my way to get. On my LCD tv only one input supported it and I had to go into the menu and enable it and stuff. I tried it, wasn't impressed and never really messed with it again. On my C9 its all automatic so I just kind of go with it.
The thing I like most about 4K uhd is the sound. To me the soundtracks are better and I like Atmos/DTS X. And again your system won't do Atmos or any of the other newer formats.
And not to mention 4K blu rays cost more.
Again, nothing more than my opinions incase you were interested. If you want to get one, get one. That is half the fun of this hobby for some people. Trying new stuff out.
After everything I said I am still considering getting a better 4K player than the one I have because it was a fairly cheap model and an early version so it lacks some features newer and more expensive ones have. It just seems like kind of a shame to pair a 100 dollar player with a thousand some dollar tv lol. So in the end I am not even going to listen to myself lmao. Just don't be shocked if you get one and you are not floored by the performance. I really wasn't. But then you might see something different than I did. It happens.