Spotify on Mac. It’s Chromium-based, so, of course, it’s slow. Specifically, search is excruciatingly slow, removing an album from your library redraws the whole page, and—most frustratingly— as soon as you lose internet connection, your perfectly nice and readable page get replaced with “Artist pages are not available offline”. It’s a list of tracks and albums which is updated (at most, on average) several times a y…
I use Spotify all the time on my 2016 normal-powered Macbook Pro and I don't experience any of your performance problems. Everything's lightning fast including search, and I've got 10,000's of tracks saved in 100's of playlists.