Thanks for the answer! From the other answers I got in this thread it seems it’ll be safe to turn off Secure Boot, so I guess I’ll do that and try to boot again.
This was very informative, thank you! One more question: what are the differences between Mint Cinnamon and Mint Xfce?
Thank you for your response! So I can select Continue boot, install Mint and then reenable Secure Boot after I’m done installing?
Continue boot