I actually had something similar setup on my previous phone - triplebooted SailfishOS and two LineageOS installs. Only issue is I never got things like the cam

I actually had something similar setup on my previous phone - triplebooted SailfishOS and two LineageOS installs. Only issue is I never got things like the camera working in my port of SailfishOS, and some Android apps I used wouldn't work when the phone was rooted, which is why I had one rooted Android install and one unrooted. Also, in order to switch you had to reboot into recovery and flash a zip changing which partition to boot from. Worked relatively well though.