The phone app works just fine (I find it as easy to use as Spotify with a way more vast catalogue + a better recommendation algorithm (for me) + skiping ads on youtube + being able to use youtube with the screen blocked is a huge thing for me, especially for podcasts + good interaction with my car's android auto).
When I am at the PC I use the browser version, or even youtube itself (the current version is VERY similar to spotify, not to say it is a copy lol). Not sure why would I need a native windows app. Maybe I do not listen to music on my PC as much as you. (You could also connect your phone to your pc, via cable or bt, and control everything through the phone app).
Not trying to sell it for you. Spotify is very neat, user friendly, and works amazingly well. Just telling you my experience. Of course that there is a something like an "adaptation curve" everytime we make a change for something new. In my case, after a couple days adapting to yt premium, I would never go back to spotify.
ps. I am talking about YT premium, not YT music. Here in Br YouTube Premium goes for BRL$20/month, same as Spotify premium (+-USD $4/month).