Sure, I have a bitcoin only business, it's https://21baller.com

I purchased 25 sets of these items as a one time thing and have sold three so far. The supplier would charge me more if I wanted more since they didn't realize how cumbersome it would be to do. A mistake has been found with the balls, and the website has not been updated (I should do that soon, good reminder) -- given the size of the mistake, it wouldn't actually be a security risk, but risks where the magnitude of the risk you are taking are not determined are the worst to take.

The profit margin would have been around 65% (though I'd call it breaking even considering my time for 25 sets), and since they aren't all that popular (though BTCsessions might do a video with them), I will likely just be taking the loss.

I used https://carrd.co to build the website (nice no-code website builder) and BTCPayServer.

I prefer accepting fiat as well and simply converting profits into bitcoin since most of the potential customers in the world pay with fiat. I charge my fiat customers extra without telling them, by having an undisclosed discount applied for bitcoin that you only get to see upon checkout: https://getchroma.co

I made my Chroma shop bitcoin only for a couple weeks -- lead to some people learning to use bitcoin for the first time because we have some pretty unique products with limited alternatives, but there was a substantial drop in sales so I had to revert it.