What is: the best way to make plex play CURRENT POPULAR music if I own it without TIDAL

You need to have this ‘current, popular’ music in the library. i.e. you need to own the files.
Then you can
use the ‘Library Radio’.
or an ‘Artist Radio’
There will be more of those ‘Radios’.


Another approach:
You could ‘rate’ your songs. Then you build a ‘smart playlist’ which includes all tracks with minimum 3 stars and and which were added within the last 3 months.
(Of course this will only work if you add fresh music all the time.)