I've been using mpv for all kinds of content and have only had good experiences with it. Only the control scheme takes some getting used to as you do everything with keybinds instead of a clickable interface.
I've been using Haruna which is a version of mpv with a clickable interface. I don't know why but mpv would sometimes lock my system, which Haruna doesn't do also.
Not sure about now but I think Dolby Vision didn’t work very well with IINA the last time I tried it. For me, Infuse just works with anything I throw at it and has Jellyfin support which altogether makes $15/year well worth it for me
If you have an LG smart TV running WebOS, there's an exploit in the web browser you can use to gain root access and install the homebrew channel. It's literally just going to a website and clicking a couple buttons. From there, you can install a number of different homebrew apps including the aforementioned Jellyfin, as well as ad-free YouTube, RetroArch and of course Doom.
The homebrew channel also lets you run an ssh/telnet server that gives you remote access to the TV's back-end command line and filesystem. I found this functionally extremely useful for allowing the TV to still get online while having it behind a DNS server that blocks access to all of LG's telemetry domains.
This gets me 4K HDR and Dolby Vision support. 24Hz frame rate matching, and lossless audio to my 5.1 audio system. And a UI that doesn’t lag or have any ads.
Nvidia Shield plugged into my TV running Jellyfin. Occasionally if I get playback issues I'll open with an external player like Just Player, Vimu, VLC, etc.
Jellyfin used to be pretty rough with playback, especially if you watch with subtitles, but in recent months I've rarely had playback issues.
On PC I use mpc/madvr, but usually just to check a video file, not to watch a whole movie. I save that for the TV.
I did that the first few times I downloaded Dolby vision after I found it wasn't being outputted correctly, but copying over the gigs of content to a usb stick to play on stick felt tedious so just went with regular hdr uploads after that.