Beside your arguments. a song has around 3:30 min Playtime - so playlist with 3k titles is around 150 hrs playtime - would not make any sense to me.
But as you said - other can do it with ease.
I just created a playlist in Roon, with out of Genre Jazz. 5001 Tracks, 379 hrs Playtime - I took Roon seconds to do that.
ROSE is not that bad. Generally i enjoy to use it except for the missing tags, which is really bad for me, and inability to quickly/instantly add new tracks to the DB which is also really bad.
For example i like to concept of divided DB which is only uploaded to the client software after starting the app. There a “recommended” playlist generated whenever the DB is reloaded. I use that feature regularly… it takes a few hundred albums to create the suggestions/recommendations.
Now it would be nice to add some options like genre, publisher and so on to create the “recommended” section.