I hasn't heard of this streamlined version of Android until today.
When my phone dies or is too slow to do much of anything more, I was going to get a flip phone as my tablet does most things now except Spotify. Flip phones have their proprietary OSes that aren't compatible with Android apps so I'd need something that is.
So I stared looking at cheap phones at Chattr and came across the Nokia 2.1 phone with Android Go (https://www.chatrwireless.com/web/chatr.portal?_nfpb=true&_pageLabel=PhoneBrowseFlow&phoneId=2.1CH). So I read a bit about it. If you're interested, check out this article at Android Authority (https://www.androidauthority.com/android-go-773037/) which also reviews some phones with Android Go, including the Nokia one.
Android Go is a lighter version of Android and has recommended 'lite' versions of popular apps that run well on it. The OS and the preinstalled apps also take up less space. But you still have access to the full catalogue. The lighter versions of the apps are more basic (and smaller) but still functional. Google provides a little more detail about Android Go (https://www.android.com/versions/go-edition/). Click on the developer section and you find out that they're encouraging developers to make more apps specifically for it but also how to write lighter code in general.
And yes, Spotify has a lighter version called, wait for it, Spotify Lite. I know you couldn't stand the suspense. Here's a list of some of the lighter versions of popular apps (https://www.androidauthority.com/android-go-lite-apps-891592/).
There's also nothing to stop you from using the lighter versions of apps if they have the features you need thus saving RAM and load times. Probably less room to bury malware, too :)