That is not the purpose of Secure Boot. The purpose is to establish a chain of trust of all code running on the system from boot and as such eliminate rootkits that can hide from the OS. A classic example is the MBR bootkit. Of course that this is mostly out of the window if at some point in the chain the trusted code just runs untrusted code, like the bootloader or the OS running unsigned code. Also the implementation is terrible, a proper implementation would allow the user to use their own certificates and only their own certificates, otherwise a compromised generic certificate fucks everything up like it already happened.

I need it for my Windows 11 install for a few games on there that require it.

To play Valorant, why else

Secure boot is in case the OS gets tainted. It only allows a signed OS to boot.

For example when new nvidia drivers are autocompiled into my Tumbleweed kernel during an update, on reboot the srcureboot asks if I want to view the new key or allow it. I then have to enter a password to add the key...otherwise it won't boot with that kernel.

You’re thinking bitlocker not secure boot

Edit: I was incorrect, see below.

I am using secure boot on a laptop with password-protected UEFI and disk encryption.

That's exactly mz setup, as I need to leave my work laptop unauthorized in a shared space for prolonged periods.

Can't set up secure boot though because even fckin lenovo doesn't provide the needed bios options for Linux nowadays -.-

Secured boot has nothing to do with encrypting your hard drive.