Oracle 21c: ora-00059 even after upping db_files

This may be related to our unfamiliarity with CDB/PDB installs. We have an Oracle 21c db that has just one PDB. That PDB had the default db_files of 200 and "select count(*) from dba_data_files" currently shows 182. We attempted to create a new tablespace with 13 datafiles and received an ora-00059: maximum number of datafiles exceeded.

Not much of a surprise. We changed db_files to 300, bounced the database, confirmed the db_files parameter was at 300 and attempted to create the new tablespace. We still received the ora-00059. We increased the db_files to 500, but we are still getting an error.