I mainly listen to jazz in all its infinite, glorious variety.
I use Deezer and haven't found any significant omissions or many recordings I haven't been able to find. More frustrating is that because many albums are over 50 years old and out of US copyright, you get lots of spurious compilations which aren't 'real' albums.
That aside, it's great - the coverage is better than Tidal and about the same as Spotify - I've never used Google Play. Qobuz has some more recent, more esoteric content, but isn't great for older music.
There are loads of jazz-oriented internet radio stations - P8 from Denmark and TSF from France are both awesome
It might be worth having a look at JAZZRADIO.com - enjoy great jazz music. I have a subscription to their sister station for electronic music (DI.FM - £5 a month) and while only mp3, it is about the best 320K mp3 I have heard as they seem to make an effort to select well produced releases. Also they seem to be very good at sticking to the stated genres of the various channels, so I would have high hopes for their jazzradio streams.
A quick glance at the jazzradio web site suggests a lot of channels.
If you go for a premium sub, then you will need a media streamer that supports manual entry of a stream URL so that it can include your personal key - so forget about using tunein airable related junk based media players unless they have finally decided to support custom URLs like vtuner used to.
Most Streaming Services have libraries of 10's of MILLIONS of Song in every genre. They all have huge selections of Jazz.
I've not used those streaming services, but the one I use (Free Version) I can start a continuous stream by either selecting a style or by selecting an artist.
For example, if I want Jazz, I simple select one of several 'jazz channels' they have. Alternately if I want to influence the sound even more, I select an artist, for example Django Reinhardt, and it will mix Reinhardt with a mix of similar Jazz.
I believe the service I use has 14 unique Jazz Channels.
Now if you want something that specializes in Jazz, then likely you want Internet Radio. There are countless Jazz Stations around the world that stream Jazz constantly.
Khazul has provided one example -
Many equipment makers connect to places like TuneIn to get their list of Internet Radio Stations.
So, the point is, any of those Streaming Services will have a vast library of Jazz music, it is just a matter of determining how to get them to stream it to you. In my case I simply start a Stream either by Artist or Genre, and let things run from there.
With Internet Radio you don't get the absolute highest Hi-Res streaming quality but it still sounds very good, simply run a few streams on TuneIn and see if you like the quality.
So ...short version... any of those services will have an endless supply of Jazz songs to listen to.
Google Play has a Library of over 40 Million songs.
Deezer has 53 Million Tracks.
Tidalhas 57 Million songs and 230,000 Hi-Resolution Video in their Library.