Installing Windows 11?

It becomes clear to me that I need to have a clean Windows installation to solve various issues on my Vostro 270s. I would like to have two things for this matter:

1) Install Windows 11 instead of the current Windows 10

2) install the OS on a newly installed SSD instead of the HDD that came with the Vostro.

Windows 10 is its current OS (one of OSs) and it was upgraded automatically from the original OS on the Vostro. According to https://www.microsoft.com/en-us/windows/get-windows-11?r=1, the upgrade is free for Windows 10 users. How can I prove that I am a Windows 10 user?

Do I need to change BIOS Mode to UEFI from legacy ( https://www.dell.com/support/kbdoc/en-us/000190116/How-to-Enable-Secure-Boot-on-Your-Dell-Device) or enable TPM 2.0 (https://support.microsoft.com/en-us/windows/enable-tpm-2-0-on-your-pc-1fd5a332-360d-4f46-a1e7-ae6b0c90645c) if using a new SSD? 

BTW, I get "updates failed. Your device is missing some security and quality fixes. There were problems installing some updates, but we'll try again later." for the Windows update.