Yes, zoning laws generally frown on improperly zoned home businesses (although they rarely ever actually enforce it unless a neighbor or homeowner's association complains).

However, there is a ridiculously simple workaround for 100% online businesses like yours (and mine) - get a private mailbox or virtual office & register your business to that address!

I've gone through the same process multiple times, both for myself & a for a few web design & marketing consulting clients. (note: I'm a startup & entrepreneur consultant, not attorney, so my legal knowledge is limited to what I've learned from both my own clients & working at legal startups Lexicata and LawKick - an in-state attorney will have more specific advice)

While you're right about state variations, generally speaking it doesn't matter where you're actually working from - what matters is where your business is registered. If you don't have any inventory, customers actually coming to your house, etc. (in other words there's no actual business taking place at your house), then you're technically on "Online Business," regardless of the address on your business license.

It's not uncommon for online businesses to register themselves using the address of a private mailbox (e.g. from a local UPS store) or sometimes a virtual office. If there really is absolutely no physical front to your business, many startups get a mailbox & incorporate in Delaware or Nevada for their business-friendly state laws.

Think about it this way: if your business isn't actually registered to your home address, zoning isn't an issue, because at that point you've essentially made yourself a "remote employee" of the company (even if it's registered in Nevada).

Feel free to reach out if you'd like some resources on the topic or to hear how the process worked in the long-term for myself & my clients.