Zend certified PHP/Magento developer

How to transfer orders from Magento 2.4.2-p1 to Magento ver. 2.4.5-p1?

Magento 2.4.2-p1
Smartwave Porto theme
13 Amasty extensions 

I have a production Magento 2.4.2-p1 website with 2 stores. We are having lots of problems with this site which I truly believe might be a combination of using the official Magento Migration tool when we migrated from Magento 1.9.x and issues caused by Amasty extensions. We were able to sort some of the problems out but certain serious issues persist and I may not be able to resolve these.

I have, therefore, built a brand new Magento ver. 2.4.5-p1 website without using any Migration tools. I tried to use the Export/Import feature to transfer products over. Unfortunately, only about 2/3 of all products transferred while I keep getting Error messages on the rest. I hope to straighten that out and transfer Customers in the same way without using the Magento Migration Tool.

What would be the best way to transfer orders over? And are there any other tools to help with migrating the remaing 1/3 of products should I not be able to make it work via the Export/Import process?