Ask HN: I'm going to launch a SaaS startup soon, what taxes am I liable to?

I'm launching a SaaS startup in the coming weeks in US, Canada, European Union, United Kingdom, Australia ( Australia and New Zealand ), and India.

I was wondering what kind of legal taxes would I be liable to.

Some helpful information : the startup is not registered yet ( it'll be registered as a C-Corp in Delaware if things work out ), rn it's based out of India.

Apart from filing for GSTIN and IEC ( Importer/Exporter code ) in India, what other legalities would I need to fulfill in the rest of the mentioned locations to start accepting SaaS payments?