I used adoptable storage on LineageOS, and you do in fact have to choose whether apps live on the external or internal storage. Worse than that, in fact, you do

I used adoptable storage on LineageOS, and you do in fact have to choose whether apps live on the external or internal storage. Worse than that, in fact, you don't get a choice at installation time. All apps are installed to external storage by default, and the vast majority of apps that I've tried simply don't work until you go into app settings and move it to internal storage. In most cases they crash immediately at startup, but there are occasionally other failure modes like drawing the skeleton of the UI but none of the interactive parts. Adoptable storage also has the neat failure mode that if you accidentally pop out the SD card while the phone is running, you're in for a real treat. Also, anytime anyone asks about adoptable storage in the LOS subreddit, the devs always respond that the feature is broken, will not be fixed, and they don't recommend using it.