CK3/CKIII Multiplayer joining takes a long time

[JayTuut]

Information​
I have verifed my game files (Steam only)​
Yes

I have disabled all mods​
Yes

I am running the latest game update​
Yes

Required​
Summary​
CK3 Multiplayer joining takes a long time

Description​
CK3 Multiplayer joining takes a long time

Steps to reproduce​
Step 1. Join Game
Step 2. I paste his game ID and join
Step 3. Wait for about 10-15 mins, progress % bar on his side is very slow for my joining

Game Version​
1.9.2.1

Platform​
Windows

Additional Information​
Affected Feature​
Gameplay
Multiplayer

Save Game​


Other Attachments​

Has been an issue since the game came out.

Even on LAN, it takes about 10 minutes for the file to go through, ck2 never had this issue and I'm confused, me and my brother are trying to play, the download/upload for both of us when he's at my house and at his house is 100/40 at both places.

What's going on?

The game save files aren't that large.. so why is this happening?

I was advised by Andrew in my tech support thread to test on EU4 since it has both steam MP servers and Nakama servers, here were my results:
==
I tested this with another paradox game, EU4. My Results:

1 min 21 seconds --> Nakama

23 secs --> Steam

So a lot quicker via Steam servers. The EU4 save file is 10MB while the ck3 save file is 30MB.

7 mins 15 seconds for CK3.... really long time (it seems to have increased recently since this test to about ~12 minutes)

===
I also tried via a VPN as suggested and via a third person, still no luck, same issue. There are multiple other threads on this same topic as well.

I contacted support again and they advised to make a new post considering my last one was older/archived.

[Mahok]

Did you find a solution?
I have the same issue here with 2 PCs in my local network at home.

This is why we don't play CK3 any more (and the desync after loading MP games).