What about to migrate Azure VMs to Azure VMware Solution first, as an intermediate step. Then using HCX to keep data in sync with your On-Premises environment as a DR scenario, then just run a fail-over - definitely you will increase the cost using AVS but you will significant reduce the downtime.
Another scenario, using AVS, might be to use VMware SRM - between AVS and On-Premises - never tried but might be something which can be analyzed.