Just wanted to say here that after a long night of troubleshooting, our issues were solved by putting all the disks for our composer clones on a SATA controller instead of the LSi one.
Machines went from freezing on boot to 20 second startups on Win 10 1910.
Tested on ESXi 7.0 and 6.7U3, using Horizon 7.11 and vCenter 7.0
Thanks