All user profiles use the same "installation" of an app; they just run their own instances of it. That means that you can only run an app (aka a package of a specific name) at the same version level, and with the same signing certificate, in any profile. (Some app developers use the same certificate for APKs uploaded to multiple repos/stores, while other devs use a different certificate to sign the F-Droid version vs the Play Store version, etc. That's why sometime you can install apps in different user profiles from different sources, and sometimes you can't.)
If you MUST run a different version or different signature of the same package in multiple users, your only option is to rename the package. This can be done with an app like App Cloner (which currently doesn't work on GrapheneOS, but should be fixed when they release the next version, v2.16.13). Or you could try opening the APK in Android Studio, changing the package name manually, and re-signing it with a test certificate (Theoretically. I haven't actually done this successfully yet.)