I think Stan.store is a good company to check out, they’re addressing this pain point quite well. You could figure out what they’re bad at and that’s your gap.
- read reviews and posts about Stan
- message creators who use Stan and ask what they would change or hate
If you’re sending it to people I like docsend so I can track analytics, get notified when it was opened, and control share access.
I made mine well designed in photoshop, but if it’s pretty without substance it won’t matter, you need both.