Kodi does all of this, except remote viewing that possibly could be done through external addons, but I'm not sure about that. Some features like remembering what you were watching requires it not to be turned off. Sleep is fine however, and on my mini PC it goes to sleep when it detects I turned off the TV via HDMI/CEC connection. When you wake it up you'll be in the same place and it remembers also the time watched, while if you turned it off you have to navigate back to the place you were watching, but it still keeps the time of that file and any other one, prompting you to continue from when you left or start over. Watched files and time are saved as part of the backup that can be scheduled to run automatically in the background, so one can upgrade it, then restore the backup to get back every change to the interface, addons, configuration, etc. It also runs on phones, and I installed it also on my Pixel with GrapheneOS along with some addons, but the interface is really hard to operate there.

I am sure about Kodi not being able to perform remote viewing with the same compatibility and convenience as any of the popular dedicated media streaming platforms.

I get that you like Kodi, but listen to yourself. Kodi does all of this! Except you might need a plugin that doesn't exist for the one big feature that spurred the existence and popularity of Plex, except that some features work but not reliably, except that you need to actively manage the backend, except that the phone UI sucks.

So, there's your answer?

I'm not a kodi fanboy, and I would certainly change a few things about it if I could, but I needed a client because having a NAS where everything is stored in their appropriately named own directory makes things a lot faster; all it needs is a player on something that can mount remote directories. Also, my NAS runs XigmaNAS which I doubt could stream videos, but more importantly I don't need the stream functionality because usually I'm watching something while my SO watches something different. They're just different solutions for different needs.

You were overselling it a bit, going so far as to assume a plugin existed for it when it didn't. It gave a bit of a fanboy aura to the comment.

I like Kodi too, I've been using it since the XBMP days on modded Xboxes and still do for certain things, but eventually I needed something more flexible and something that worked over the internet. Being able to share my movies with my grandma or my next door neighbors wasn't really achievable with Kodi.