input lag on main account, no input lag on second account

I give up. I don't know how to fix this.

I have 2 accounts. My main account. And another.

They share the exact same settings (the share the same settings file)

Same sens, same settings, same everything.

But my main account has higher input lag and genuinely leads me to lose fights I would win on my second account. I test it in empty deathmatch lobbies where I move my curser and it is slower on my main account.

Both accounts have the same number of friends.

The only difference is the amount of activity on both accounts.

The account with input lag has 500 hours

The second account without input lag has 100 hours.

I even removed all connections to my main account like twitch and xbox and attached them to the second account. Xbox comes with gamepass which gives me hundreds of cosmetics from previous seasons, so a large cosmetic inventory cannot explain the bad performance either.

What am I doing wrong? It makes me lose fights in the game. It feels awful. Why would 2 different accounts feel different to aim on the exact same settings?