How to list running PDB services/processes on my server without having to use the lsnrctl command

I'm currently running Oracle 19c RU 17 (19.17) on Oracle Linux 7.6 x64.

Prior to container databases, all running instances could be found in Linux using something like:

ps -ef | grep ora_smon_ | cut -f2- -d'_' | cut -f2- -d'_' | grep . | sort

I know I can run something like:

lsnrctl servacls | grep Service | cut -f1- -d'"' | cut -f1 -d'"' | sort

What I'm looking for is a command that will let me see what PDB services are running without having to log into each CDB first when the listener is down. The reason why this is important is because I will need to do maintenance on CDBs/PDBs while the lsnrctlt service is offline.