So, the situation is the following:
for 1 year, i had this configuration working perfectly:
one 6TB HDD for parity
two 6TB HDDs for data.

I just bought two new 6TB drives, and wanted to add them to the array as data drives so i will get one disk for parity and 4 for data.
After adding the hardware to the server i added them "disk 3" and "disk 4" slots in the array.
(I did not run pre-clear or something like that, but directly added them)
It took some time to update the parity, and i got to the following place:
As i understand that is expected, because now the parity drive includes what is on the two brand new drives, but there is no file system on them. So i go and run the format on the bottom of the page. 
Format starts, page refreshes. and few seconds later i am back to square 1, like i never clicked the format button.
when i opened the console, i see this:

I did try this several times and with the same result. I restarted the server and still the same thing.
I have try to start the array in maintenance mode and format it like that, still same thing.

While reading around i found out about "unassigned devices" plugin and tried several things with it as well.
I stopped the array and removed one of the drives and using "unassigned devices" ran pre-clear.
it was perfectly fine, no errors. I added it back to the array and waited around 8hours for the parity to finish rebuilding.
when trying to format i get the same problem.
I have also tried to run the "erase" command from "unassigned devices" on one of the drives, but same result.

I have also tried to format it using "unassigned devices" but there i am not sure what is going on, because after page refreshes, i get no messages, but also the "FS" column for the drives is empty, so i have the impression that it did nothing. Anyway, after i added it back, still same as before.

if i was adding only one drive, i can assume that it is broken out of the box, but what is the chance both new drives to be broken?
i have the feeling that i am not doing something correct here.

I need to save the data on my original two drives, but the new ones i do not care, they never had any file system on them, let alone data.
I was thinking if i start from scratch (let say new install of Unraid, or somehow new config for the actual array) can i keep my data from my original two drives as well?
Of course i prefer to fix this one if possible, but i have already spend almost 4 days testing different ideas i find, so what is 2 days setupping Unraid from scratch

Diagnostics file attached.
 

diagnostics-20221120-1451.zip

Update unraid, 6.11.2 has a bug with formatting.

lol if that is the problem it will be super fail form unraid side. I updated few weeks ago, and literally after the reboot was done, one of my nvme ssd drives stopped working, I just assumed that it is coincidence, and the drive just died for unrelated reason, but maybe it was not. 
Anyway, thanks for the info, I did not know there is even newer versions, i will try 6.11.4 and if it dose not resolve it, i may try with reverting to something older. Hope no other issues will come from this.

Ok, yea that was the problem. i updated to 6.11.4  and it is resolved.
Thanks a lot for the help, you saved me so much time