There is absolutely no rationale for “You should NOT run any other services on the same system as your PBX.”
If your using Debian or anything not directly supported, It is not that “you’re not using” it’s that "you can’t use it (because we rely on a no longer supported obfuscation) and don’t care "
be careful with your use of PHP 7 , many distros now are at 7.3 (current) FreePBX hobbles along with 7.0 in some areas, same areas will fail at +7.1
JM2CWAE