Impossible to Sync Brave on my new Mac

Hi, I just changed my computer from a 2015 MacBook Air to a 2019 MacBook Pro.
I finish my settings, especially by installing Brave, and … Problem! Impossible to sync the old one with the new one because the new one doesn’t give me the possibility to fill in the 24-25 or 26 words to do so.
When I’m on Brave, I go to “settings”, then to “synchronize”, I have only one choice “manage your synchronized devices”.
If I click on it, I find myself in a list of empty devices…
If I leave the synchronization chain and validate… I’m back to the previous menu, with no more choice, only “manage your synchronized devices”, without being able to enter my synchronization phrase again…

I uninstalled several times, tried to switch back to previous updates… I’ve been spending all my time on it for three nights now and nothing to do… which is why I’m here.
Please help me.

Did you click on that? It’s an expandable menu…