I have the opposite use case where I need to have two Signal accounts on a single phone. Having Molly alongside the official Signal app was always the solution, but I wish Signal would allow switching between profiles, or Android would allow arbitrary user accounts (I don't really want to add Signal to my work profile).
Android work profiles allow you to run multiple isolated copies in parallel - with separate address book and all. Works very well for Signal. I wish there was something similar for iOS.
There are some tools available to make management even more straightforward, like Insular, a fork of Island: https://f-droid.org/packages/com.oasisfeng.island.fdroid/
I believe you can use Samsung secure folder to do something like this, I haven’t quite tried it yet though.
Beeper allows multiple accounts from various apps in one chat app FYI
Android 15+ has Private Space which is basically an additional work profile but managed by the system and not a third party app.
https://support.google.com/android/answer/15341885?hl=en