Zend certified PHP/Magento developer

We’ve had no orders for 3 days after moving from Magento 1.9.4 to Magento 2

Magento 2.4.2-p1
Smartwave Porto theme
extensions from Amasty including One Step Checkout

We migrated from Magento 1.9.4 to Magento 2.4.2-p1 using the Magento Migration Tool. There have been few orders here and there but we have really gone down in order numbers – we had absolutely no orders from customers in the last 3 days! The shopping cart does work as I place test orders all the time.

What does one need to check in this situation? Would it be related to SEO, robots indexing our site etc.?