2019 MBP 16" 2.3Ghz i9 severe thermal throttling (Catalina 10.15.5)
Thermal throttling is normal behavior for laptops.  However, I did not expect the extent to throttling in everyday applications.
While Cinebench R20 shows robustness against thermal throttling, Adobe Premiere Pro thermal throttles right away.  The only explanation I can think of is that Cinebench R20 does not engage GPU while Adobe Premiere Pro does.  When CPU + GPU are both used in conjunction, thermal throttling happens immediately.
I suppose this is a limitation of laptops.