Yes, you understood correctly, when I go to the Mods tab on the Eu4 launcher click on Mod Tools and click on Create a Mod and fill the information out, it does create a mod file in the respective mod folder with the name I gave to it however it does not show up on the mods list on the launcher even when I restart the computer/launcher in case it did not load the new created mod file.
I do not use any anti-virus software, I have been using computers ever since I was a kid and have never used a single anti-virus program, even the Windows Defender is practically shut off, when I checked the Ransomware protection tab of the Windows Defender even that was turned off (by default I guess?) even then, I tried turning it on and adding Eu4 and Steam on the list of trusted apps, that did not solve the issue as well.
Like I have said at the beginning, I cleanly reinstalled the game at least 5 times now, every single time i unsubscribed from all the mods on steam workshop exactly the way you described in your latest answer, I manually deleted all the mod and eu4 related files everywhere on my computer namely; the files in steam/steamapps/common/Eu4, steam/steamapps/workshop/236850, Documents,ParadoxInteractive,Eu4, even the launcher files in UserName/AppData/Roaming/ParadoxInteractive and UserName/AppData/Roaming/paradox-launcher-v2.
I never used the Paradox website to subscribe to a mod before until I started this thread so unsubscribing from the mods there(which is none) would not change anything since there was never any mods subscribed from Paradox website.
I do not know if there could be more eu4 related files in a computer so, this one time I even try downloading the game in my other disc, I usually keep my games in my HDD D// disc but when I was constantly clean reinstalling the game, this one time I even tried downloading the game to my SSD :C// disc by creating a steam file in the disc in case that would help me, unfortunately, it did not.
I almost literally tried everything that can be found online with a google search of ''Eu4 missing mod descriptor file'' or ''Eu4 mods start missing descriptor file after restart'', I mean there are not that many things to be found with a search like this because I am pretty sure I am the only person experiencing this but I tried every solution people have used to having their mods missing descriptor files in different situations.
Funnily enough when I was trying to fix my problem, I even found the reddit post you made about clean reinstallations, and whenever I cleanly reinstalled the game I followed the steps you wrote there.
I also should add, I bought Hoi4 way before I bought Eu4 and when I first bought Hoi4 it had a similar problem, it would say ''Missing Descriptor File'' to some mods when I first installed them but in time I fixed the problems with most mods by clean reinstalling them by unsubscribing and deleting the mod files in both steam folder and the documents folder then resubscribing to them which also fixes the problem I have with Eu4 right now, like I said the mods start giving the error after I reboot the game for 1 time so if I clean reinstall the mod like i described before they work again, as long as I do not restart the game. Unlike Eu4 though, when I used this fix for Hoi4 it worked after 1 clean reinstallation of the mod and never created a problem ever again, I used mods for hundreds of hours, when I bought Eu4, Hoi4 started doing the exact same thing Eu4 is doing right now which is understandable because they share the same launcher(?) I have not tried this with Steallaris yet but I can bet that I will experience the same exact thing with any Paradox game since they all share the same launcher(?) I do not think this is a problem with Eu4 I think this is a problem with the launcher.