Concrete proof finally provided that the 2002 error has NOTHING is server side issue

[Cadmar]

I don't really think OP has any concrete proof.
Basically Japanese side agreed this is client side issue (player) and suggested the following 3 methods (copy word to word)

対策方法1：WiFiの接続方法をIEEE802.11nに変える
もし11acで無線接続している場合は通信品質が悪いことが多いので、速度が気になるところですが11nで接続しなおしましょう。
11acは通信速度が速い特性がありますが、障害物に弱い
11nは11acよりも通信速度は遅いが、障害物に強い
障害物を超えるごとに電波はどんどん弱くなっていきます。

This is to suggest to change type of WIFI connection from 11ac to 11n and basically concluded:
11a provides higher speed but signal will be weaker if there are obstacle (like metallic/concrete object)
11n is slower but stronger if there are obstacles

対策方法2：次世代通信方式11axが使えるルーターに変える
11axは超高速通信規格でWi-Fi 6と呼ばれるものです。
11axは「11acと11nの良いとこどり＆通信速度が速い性質の電波」で通信品質も格別です。

This method is to suggest to switch to WiFi - 6

対策方法3：LANケーブルで接続する
まあ、確実ですね…。
ルーターが近くにあってパソコンやPS4と接続可能であれば検討してみてください。
なお、LANケーブルは見た目は全く同じでも規格があり、古すぎると通信速度・品質に影響が出る場合があります。

Last method is to suggest is to just abandon wifi and use direct cable connection.
Simple and straight foward.

They also suggest to not have anti-virus program to be running at back ground.

After SE patch, I am experiencing only 2 x 2002 from previous 8 x 2002.
This is my computer environment:

This new i7 CPU with 3080 GPU is connect via direct cable, no wifi
As the system is for gaming only (no surfing, no youtube), there is no anti virus program since i am not installing anything beside steam games.
My router is pretty old that bought 6 years ago and i assume that is why i am still encounter 2002 occasionally
I bought the new wifi6 router and will see if i am still having 2002 after installation

Let’s just say for a second that I accept this answer. Doesn’t it still seem absolutely insane that anyone should have to jump through those hoops to play a modern AAA game?? What other game is the user expected to do this? Come on.

[Divinemights]

Let’s just say for a second that I accept this answer. Doesn’t it still seem absolutely insane that anyone should have to jump through those hoops to play a modern AAA game?? What other game is the user expected to do this? Come on.

This is not a fix.
Just a workaround to minimize your chance of getting 2002 (not saying 100% you won't)
I switched to that new router (direct cable connection) I bought and did not encountered a 2002 for a 6,500 que to Levithan at 7:30 PM and able to play by 10:30 PM
I kept my machine clean of 3rd party programs that will not taking bandwidth while I que.

It works for me but it doesn't works for everyone because everyone's system is different.
Believe it or not it is up to you.
I am in same boat with everyone that works 9 to 5 it is just I understand the current situations happened in the world.
If you choose to deny this and just want to blame on SE, that is honestly choice of yours

My ISP provider is also seems pretty stable to provide their service, just want to add that, much better than comecast I think
It is no doubt SE's IT team is believing 2002 is player side issue (true or not true) and Yoship is basically taking feed back from his IT team.
I am just not sure where this idea of SE is lying coming from since from their IT team's response for 2002 in 2014 is already showing that

[Bertpocalypse]

This is not a fix.
Just a workaround to minimize your chance of getting 2002 (not saying 100% you won't)
I switched to that new router (direct cable connection) I bought and did not encountered a 2002 for a 6,500 que to Levithan at 7:30 PM and able to play by 10:30 PM
I kept my machine clean of 3rd party programs that will not taking bandwidth while I que.

It works for me but it doesn't works for everyone because everyone's system is different.
Believe it or not it is up to you.
I am in same boat with everyone that works 9 to 5 it is just I understand the current situations happened in the world.
If you choose to deny this and just want to blame on SE, that is honestly choice of yours

My ISP provider is also seems pretty stable to provide their service, just want to add that, much better than comecast I think
It is no doubt SE's IT team is believing 2002 is player side issue (true or not true) and Yoship is basically taking feed back from his IT team.
I am just not sure where this idea of SE is lying coming from since from their IT team's response for 2002 in 2014 is already showing that

To further this,

Its snowing outside,
Wear a jacket.

There are connection issues,
Do your best to mitigate any potential network issues.