For native 4k content, it doesn't make that much of a difference, but it's there. Majority of the gains actually come from good upscaling of 1080p content which is plenty.
For 4k, the absolute best performance will come from either a full Bluray rip/REMUX (untouched) or a high quality encode(15-25GB, HEVC main 10), combined with an excellent renderer.
If money is not an object, I'd highly suggest putting 80-90k on an HTPC(Ryzen R5, RTX 2070,...) and get proper MadVR set up for dynamic tone mapping, excellent upscaling, dithering and anti-aliasing. It really makes a difference, especially on 1080p upscaling. If your main PC is in the same room, just put a long HDMI cable to the TV and that can be done too without extra cost.
You can also go for importing or getting an Nvidia shield TV 2019 from a friend which also has AI upscaling that actually does nicely (it won't beat NGU algorithm in MadVR though). One benefit of Nvidia shield also is that it'll also upscale Netflix, prime and other OTT content.
If you just want plain streaming and have a good router, you can put an HDD on your router and get SMB set up. Your router needs to be at least decent though as full REMUX can be upto 100 Mbps. This combined with how your TV buffers can cause video pauses. Alternate solution is Plex, which can also be done using a PC as Plex server. (I have over 3TB shared over my network using Plex and even the 50+ GB REMUX play just fine)