eBird has a free course like this, called EBird Essentials. Although that may be more about how to use the platform effectively rather than how to best collect data - the two are related though imo as part of using a citizen science platform effectively is learning how to make observations that are most meaningful to science and are more likely to be identified. I think any major citizen science platform should have some sort of introductory video/course.
I think it’s not very feasible to have an iNat course that gets too specific on best photo angles or best equipment for different taxa as, well, you could be observing literally any species on Earth, versus platforms that are more limited in scope like eBird, BugGuide, Bumblebee Watch, or any number of others. The angles you’d need may differ on a genus by genus level, and as others have mentioned equipment can be a huge barrier to novices and hobbyists (though mentioning what professionals use can still be valuable!). But I think some basics about how to effectively observe and document nature/natural phenomena, and how to collect good metadata that will make your observation useful to science, are certainly within the realm of possibility.
(This being said, if experts in a particular field would like to contribute their knowledge and advice for photographing/documenting certain taxa, perhaps these could get a series of written articles? One a week?)