Questions Big Commerce Taxes

One of our customers has the free Avalara plug in for Big Commerce and the expectation was that we would just import the tax data from Big Commerce.

Unfortunately, the only way to do that is to have Avalara installed on Acumatica, which is a huge expense for nothing. Acumatica apparently has half the solution according to this post from Karthik in Community:

We do have this feature already. If the Tax Zone has the External Tax Provider checked, then the connector will automatically create the missing taxes received from the external system automatically. But this is half solution. Because only the Tax IDs are created but not the tax rate. Meaning when the order is invoiced, Acumatica will recalculate and remove the tax rates from the order because the taxes does not have the tax rate. We are in the process of developing a feature called “Do not recalculate taxes” feature that will make this solution complete by retaining the tax rates from external system. 

I asked when they planned to fix this and I was privately told it was on the road map for 23R1. Our customer is refusing to buy Avalara for Acumatica and is justifiably enraged about having to manually create substitution tables to make it work.

Does anyone have any workarounds or processes' to recommend?

Thank you.