[beagle3]

Likely not ; they might be, by chance - but the exploits are often for bugs in places like media parsing libraries (e.g. jpeg decoder), which are not usually modified in those alternatives.

Different compile settings might render an exploit ineffective. But I’d expect any remotely popular Android derivative (e.g. lineage) to be tested by the attacker - and even postmarketOS, which is not Android based, is likely to use some of the same media parsing libraries.