I tried using UVR5 on an old recording and found the "best" result using the following settings:
Choose process method: Demucs
Choose stems: Vocals
Segment: default
Choose demucs model: v4 htdemucs
The result wasn't perfect, but I guess it varies depending on what you feed the program. UVR5 managed to separate some chatter, but most of the "background chatter" seemed to be integrated in the instrumental-file so for me it worked best with clear speech. It also made it a little easier to "see" the talking when viewed in Izotope RX. Not sure how much I will use this going forward, unless there is very obvious talking.
Processed a 1h7m file with the settings above, it took about 1h38m (1.47x realtime) from start to finish on my 2019 iMac (3GHz 6-core i5 40GB DDR4 RAM).