QR Code using HTML and CSS

Hi Front-End Mentor Fam!

This is my first project submitted! Would love any feedback you can offer!

Areas I was unsure of is my use of Flexbox, and whether there was alternative way to reach the result?

What use of Semantic HTML would be standard practice in a project like this, and is it necessary as it seems quite small scale?

What are other best practice could I use to improve? and any recommendations for extra reading?

(Extra Question - Best method to not go crazy when hitting an obstacle? Lol)

Thanks :)