I notice that when I use this feature for instance when other half or more rarely myself has a Zoom call I limit upload to 50KB/s a bit under half of the maximum on my bored band connection. I untick it again either if Zoom call has finished or I am uploading using my phone's 4G which is rather faster. If I tick it again it defaults to a limit of 100KB/s rather than the limit I had previously set.

Worth putting in a feature request?