Battleground Duo : I have less time to manage my cards

Hello, during a Battleground, I’m systematically several seconds out of phase with my teammate.
The battle starts at the same time for both of us, but ends 2 to 10 seconds later for me (it grows with the number of turns).
As a result, at the end of a battle, I have much less time to rearrange my cards.
Please note
_ We have the same graphics card (RTX 3080)
_ My CPU (core i9) is more powerful than his (core i7).
_ With or without VPN makes no difference.
_ The problem predates v.30.2.
_ Whether it’s me or him who invites the other makes no difference.
_ I’ve reinstalled the application, but no changes have been made.
_ I even deactivated my anti-virus momentarily to check if it was the cause: no, it’s not the cause either!