My use case was, I was building a website that uses HTML canvases + text and emojis to let users build custom greeting cards. I wanted users to be able to share their cards with their friends (or save it for later), but I didn't want to deal with signup or saving stuff to a database - so I just let people generate a long link that contains the card content. Since we were only using emojis and text, and since I was ok with just using one type of font, I figured I could shrink that info into a link - even if it's ugly[1]
When I first stared, I just used "Impact" font (I wanted a meme vibe), and it worked great - until I loaded it on my phone. So then I found a similar-ish font on google fonts, and that's when I first started seeing race issues. I spent some time messing with it, added preload, but it still doesn't load consistently. Especially I've noticed that the images that are used for the inside pages of a card (which are pngs generated by setting up a canvas then saving it as a blob) seem to load with a default font in race conditions. It all works again if people click to that image and load the actual canvas, but I doubt some people will do that. So it's very frustrating and I really wish there was a better way - because there really are cases where a specific font is necessary.
I think it's probably still not fixed, but here's an example of the type of load that was causing me problems.
[1] https://emojify.cards/?canvas-0=HEY+357+576+6.417+9.018+0+0+...