Outlook clients using Outlook Anywhere Online mode extremely slower when using UAG 2010 for publishing Exchange 2010

Good afternoon!
I have a similar situation with clients Outlook 2013/2016 and UAG 2010 SP4 Rollup 2 (4.0.4205.10200)

https://social.technet.microsoft.com/Forums/forefront/en-US/d280bcb8-5e3d-453d-ac7a-993c116ba9bb/outlook-clients-using-outlook-anywhere-online-mode-extremely-slower-when-using-uag-2010-for?forum=forefrontedgeiag

Tell me, how do I resolve this situation as mail synchronization 3-5Gb sized box can last for several hours.
Thank you.