yeah it's not the best replacement, but basically what I did is setup a "YTBox" app that takes a youtube link, downloads it as mp3 or mp4, and then auto syncs it to my icloud drive, and then I just listen from my iPhone either using the music app or VLC/Files.
so yes I do have to make a curated list of what I want, but it saves me $17/mo. if you're okay with downloading, then it's worth it.