The commentary factor is weird. There was one mug ATP tournament recently where stream speed was fine for the first four days and then when commentary was added for the weekend the streams for that tourney had a longer delay. On the other hand for both IW & Miami ATP streams have had no commentary whereas WTA streams have and yet ATP streams have been around 7 seconds behind the WTA streams.
Yeah the ATP 500 and above streams seem really slow with or without commentary. Some of the lower tier events have an ok speed until it's relayed with commentary on. Since they relaunched the WTA streaming it seems to either be the challenger type stream or the slow new one for bigger events. Some of the international series events used to have a decent speed stream :( The Australian Open one was much slower this year as well. The umpire chair bot must be happy