I have the physical hosts up on 5.4.0 now, this is the kernel that shipped with Ubuntu 20.04. It is not entirely stable on machines which serve as NFS servers which two of these machines do.
I have built 5.3.0 kernels which were previously stable but can not boot into them because automatic backups are running. Also I don’t know if MY 5.3 kernel will be stable as Canonical applies some patches that will not be present but the 5.3 kernel is no longer available as 19.10 is past END OF LIFE now. I will attempt to do so tomorrow evening.