The High Frequency snapshots option may no longer be available in VLCR.
The option may be visible but then later greyed out or no longer visible in Edit Protection Group wizard.
The ESXi and vCenter are running on supported version.
You may see an error in the VLCR UI as below
ERROR: No hosts in vCenter <vCenter.IP> support high-frequency snapshots.
VMware Live Cyber Recovery 7.27.x
VMware Live Cyber Recovery 7.26.x
This error in the UI mentions the fact that the ESXi host does not qualify to support High Frequency Snapshots.
VLCR does not support HFS snapshot if the host falls under the following categories:
(1) Standalone hosts
(2) VSAN Witness Virtual Appliance
(3) HCX Mobility agent host.