I don’t experience problems with anything else, and none of the router or internet tests detect any breaks. So I don’t know why iNaturalist is the sole issue here.
Regardless, I suppose this won’t be changed since it’s such a minority problem for people and it’s seemingly just me it impacts in any big way. But if it could have some way to “retry” an upload, that would still save massive amounts of time in general, even for people of whom it’s a rarer issue.