Also, although i do believe many people want this, there is already TONS of competition. Social media apps all kinda have this (profile page), tiktok and Instagram make heavy use of apps/integrations such as linktree to facilitate off site marketing.
Furthermore LinkedIn is unfortunately the de facto "business card" for most people and companies. Again you can totally create an experience that tops these tech companies but it wont be easy imo and will require a bit more than a single markdown file.
Also one major question i have is how will users share their qr code? By sending the qr image as a text? Maybe as a post on social media?? (if so how can i scan the qr if im viewing it on my phone - just send me the direct link).
Bless