Steam itself is a third-party solution. If you want to publish to Steam, you have to deal with Steam. If Steam isn't working properly, unfortunately that's outside of our control and not something you can easily swap out with something else, unless you're willing to publish to a different store like Epic Games (which we also have a plugin for).
You mean, if Construct 3 users, people who sought to use your game making software, want to publish their games to the largest game store platform available? Where do you want your users to be able to present their creations? Do you want your users to be able to present their creations as intended on these types of platforms? If so, maybe it's worth diving deeper into such issues.
Clearly you do recognize that this is an issue, otherwise you wouldn't have created this thread on the Steam forums. I assume Valve hasn't been helpful in the matter, we've also tried our best reaching out to them but to no avail. This is why people are broaching other potential solutions.