Wow seams like a lot of power just to be the front end server to run some dockers and VM's but I guess it depends on the VM's.
From what you said you have your Synology NAS as your storage array. If your keeping that for your media storage. You should be okay with your setup. There is many ways you can do your connections to connect your data to your dockers or VM's The simple way is just creating SMB shares with Unassigned devices. Years ago when I was getting my feet wet with unraid. I needed to transition my setup from FreeNAS. And all my Plex Shares I just mounted it with a SMB shares till I figured out how I wanted to setup my Data array in unraid and copy my data.
Its wasn't the best way I wouldn't recommend it on 1Gig nics if your going to stream 4K video. Worked fine for me on most cases. But at that time I don't think 4k video was even a thing. So I would say it depends on your I/O Speed and NIC speed for that kind of setup. Anyway. For what your spec'ed out I would do what what your planning put the 2 NVME's in the array and make one a parity. You can put your dockers and VM's all in your array because it sounds like your data is going to be in the synology NAS. you will want some sort of backup in case your parity was to fail you in the event the other NVME fails. You could find a script to backup the array to a SMB mounted share or write one. If you dont want to script anything and your not using to much memory for hosted VM's you could also use one of the many backup dockers to back up your array to your Data synology box. this would be one way of setting things up. It would work fine till you could build something to have 1 box do all of it. If I had this Idea your doing I would run like this for a while till I could build 1 nice box running unraid. And when done find some extra data drive I could stick in the Synology box and setup a script to back up the unraid arrays and turn off and on the synololgy box. many ways to do stuff like that though. I think this is the only way I could see using a Mini with some NVME's and unraid. And memory that's a good amount of memory unless your VM's need a large amount. if this was me and I just needed this for a Media front end like your talking about. I could do this with 32gigs easy. 16 gigs would be tight. But I might be able to pull that all if I didnt have VM's. Oh and I would use ZFS format on any of the array drives. it will just slow it down.
With parity you will be in good shape.
Good luck though. I might try to build something similar with some of my older hardware to get an Idea how that might work out. I just would have to sub the Synology with something else in my old hardware bins I got some Qnaps the company retired this year. I might use that in my test case. Oh my mini would be much older though only a Dell 7060 with 32gig ram. But I can make something similar.
