Either of the two plates you propose should work for you. I don't see any apps that need more power on your list.
To consider. The C3558D4I-4L board is designed for server use and the J4005B-ITX board is designed for desktop. You are going to set up a server. If you can afford the price difference, the first one will work better. ECC memory especially, in addition to other features. Intel quicksync can only be missing if you are transcoding with jellyfin. J4005 has it, C3558 doesn't.
Keep in mind that they are both atom, performance may seem slow at some point. It depends on what you do with it. You will still be able to virtualize with KVM if you need it in the future, keeping the above in mind.
What I have seen is that both are from 2017. Perhaps there is something more current on the market, with better performance and lower consumption ...
Okey good to know that the C3558D4I-4L is for server use and the J4005B-ITX is desktop use. Also good hint with the ECC memory, i will keep that in mind. How you can see what board is for server or desktop use?
What do you mean with the Intel quicksync thing? Because actually i use hardware transcoding for my jellyfin docker on my Pi4. I definitely need that otherwise the videos are super slow.
Yeah i try to look for somehting more new then 2017
You don't need it. I use an old one because I already had it and it's free for me. If I wanted to buy now I would look the same as you are looking. Or alternatively a second hand xeon server.
Okey. The thing is i now run all the things i do over a Raspberry Pi4 and it works but is not the fastest. It is totally usable but if possible it could be a bit faster snapier. But i totally have no clue in what region i am in terms of power i need. I do not want a slow or not nice experience for a new build machine but i also don't want to crazy overshoot with CPU power i probably will not use and just consumes more power and raises my power consumption. So i try to find a sweet spot in the middle but this is really difficult...especially for my little knowledge i have in the server area.