It’s been some time, but IIRC, I downloaded W11 onto a flashdrive with the MS media creation tool, booted of this drive and did a fresh install over my W10 installation. In this process I wiped my disk. Before that I googled what to do in order to be able to install without an internet connection. This allowed me to complete the installation without an MS account. This procedure might have changed since then. AFAIK there are still some hoops you can jump through in order to get it running without an MS account.
It’s been some time, but IIRC, I downloaded W11 onto a flashdrive with the MS media creation tool, booted of this drive and did a fresh install over my W10 installation. In this process I wiped my disk. Before that I googled what to do in order to be able to install without an internet connection. This allowed me to complete the installation without an MS account. This procedure might have changed since then. AFAIK there are still some hoops you can jump through in order to get it running without an MS account.