Not sure why it was even changed in the first place, but yeah... the new user interface for the desktop app is really inefficient, frustrating, and ultimately a deal breaker in its altering how the songs that you've liked are accessed.
More specifically... taking them off of each individual band's/artist's page where it previously only took a few seconds to find and play a song that you liked through the green heart mechanism was a bad idea/move.
Furthermore... throwing them all together into a single play list is an even worse idea/move given that it now takes so long trying to scroll up and down through thousands of liked songs while trying to find whatever it is you're specifically looking for that you are better off just giving up trying to use the desktop app and switching over to the mobile/tablet Spotify app that still has your liked songs listed under the artist page, or just straight up ditching Spotify completely and looking up the song on YouTube, Bandcamp, etc.
With that... and as someone who has ever-present tinnitus in both ears from my time serving in the military that in turn makes being able to use the Spotify desktop app to listen to music through headphones that are of high-enough quality to actually be capable of drowning out the constant ringing in my ears (and in turn desktop-dependent) super important in maintaining my sanity/mental health...
I damn near beg whoever is in charge of such to re-implement the layout of the previous user interface so that the Liked Songs are moved back to the individual Artist's page as its removal with the new user interface has pretty much killed off my being able to even use the new Spotify desktop app at all (and in turn the aforementioned high quality headphones that I am dependent upon).
Additionally... might I add that putting the "About" section of each artist's page at the very bottom instead of at the very top of it is also a bad move in that having actual info about the artist listed as the very last thing on their page is really inefficient (if not disrespectful) given that it comes after other artist's work is recommended before you can even read about the artist whose page you clicked on to check out in the first place.
With that... I'd not only recommend returning the Liked Songs to each Artist's page, but also recommend structuring their pages so that it is presented in the following and more efficient order...
1) the About section; 2) the Liked Songs section; 3) the Popular songs section; 4) the Discography section; 5) the Offers section; 6) the Artist Playlists section; 7) the Featuring section; 😎 the Fans also like section.
I hope that whatever powers that be within the Spotify decision-making hierarchy that actually see this seriously consider, and really... just start straight up making moves to get the ball rolling on having at least the Like Songs (re)implemented to each Artist page, because if not... people such as myself that are a heavy, heavy users of the desktop app are highly likely to start transitioning to some other means of efficiently listening to the music that they love, which is something that I really hope I don't have to do after having already invested hundreds (if not thousands) of hours into piecing together a music library that serves as a key (if not primary) component of maintaining my sanity/mental health.