Any harm in suspending the host while leaving the GW and WS running?

I usually just suspend my host and leave the gateway and workstation as they were, running on the host.
After waking up, I restart the Gateway, and use the “Restart swdate - instantly adjust the time” on the Workstation.
Any harm to my OPSEC?

(BTW if the gateway is not restarted then the workstation loses connection after about 10 minutes, but it works until then)

Shouldn’t be. If you are using KVM then the GW timer should be updated with the host’s. For the workstation you should run sdwdate manually before browsing again.

Security Guide - Whonix