Maybe check some options with Intel N300/305. To be honest I don't know how good Intel Quicksync is, so you might need an external GPU as well. You also need a power efficient DC PSU at low wattage.
It is also important what components you put inside, like low-end SSDs have the lowest power consumption and maybe are your best bet. I would also recommend you buying a 5400rpm power efficient HDD if you need it. Disabling all unnecessary ports in the bios can also help lower your power consumption and tweaking the power limits of the C-states, and enabling C10.
My suggestion is first try to play a bit with your current server BIOS settings and the power optimization in Linux. If your power consumption at full load is like 90-100, maybe consider swapping your current PSU with a DC one, as they have superior power efficiency and after each change evaluate the performance and the power consumption both on idle and on 100%.
Thanks for pointing out the ports, I'll see which ones can be deactivated. I've been reading up on c states lately.I just suspect that my configuration leaves little room for maneuver.The microserver is currently running proxmox with openmediavault and a vial pihole on lxc. I would swap the vial pihole for a raspberry and only use OMV.
Keep in mind that RPI is good for containers, but not for virtualisation, so if you want to run some VMs or have proper expandability I would advise you against RPI.
Plus disabling the ports won't make a big difference I presume, a couple of Watts at best.
I recently bought an N100 powered firewall appliance and the idle consumption is around 13 Watts, with two SSDs and 32Gb of RAM, a bunch of USB and video ports and 4x2.5Gbps ports all switched on. People are even reporting that this can be pushed down to 7-8W, comparable to what you would get with RPI.
The i3-N305 has 8 physical cores and TDP of 15Watts, which can easily be reduced to around 9-10.