For context, it's a meditation app where people log in, meditate for a few minutes, then tell us how they feel. It's meant to be used daily. If it's not simple enough, they'll drop off, so analytics are used mostly for engagement tracking.
GA is optimised around advertising rather than engagement. It's also being blocked by browsers and it's getting quite complicated.
Heatmaps are a little useful too. Hotjar has been fine for this, but I wonder if it's a little intrusive or if there's better tools out there.
You can enable/disable specific tracking and privacy settings as you wish.
To track engagement you can use the Tags and Events features.
Happy to answer any questions!