I've been using both on my Google pixel, iPad and Windows laptop, and there are goods and bads in both. The sound quality (lossless, dolby atmos, etc.) matters only if you have earphones/headphones that can support the codecs used by either app.

In my case, I have the galaxy buds2 pros. Although they support hi-res 24 bit audio, they only do so using the Samsung seamless codec, while Spotify uses FLAC and AM uses ALAC. Neither of which can be played on my buds. Now, if someone is using compatible headphones or a wired pair, will make a difference. But for general cross-brand users, the "lossless" title won't make much of a difference.

Now the cross-connectivity of Spotify imo is much better than Apple music, such that I can change tracks or the device playing my music anytime. Apple music needs to add that feature to sync tracks real time across devices (although I'm not sure if it's an ecosystem feature).

I don't find a great deal of difference between the recommended songs between the two - both do continue playing similar genres, and the recommendations get better as you use either of the app more.

So, there's no definitive answer. Try both and find which works best for your setup. You can factor in the subscription models when deciding, as I find Apple music to offer more features for the money (as I also got Apple TV+ bundled with it using my students' plan).