No. Fiverr is the one charging sales tax because they are reselling your services on your behalf. You aren’t selling to clients. Fiverr is. So nothing you’re describing applies.
You don’t make invoices or bill clients. Fiverr does that on your behalf. This is a marketplace.
Just make sure you’re following the laws of your country. But no law changes the fact that Fiverr is reselling your services.
Never sign off that you agree to ToS until you understand them. You don’t.
This is true, but Fiver is reselling on your behalf so income tax is the issue here. So you need to deal with income tax but not necessarily sales tax because Fiverr charges that on your behalf. But the rules do vary by country, but this is resale via a marketplace, not direct sale to clients.
What I gather from accounting inquiries here is that accountants don’t understand that this is resale on our behalf.