Tax calculation in the EU is very specific and I don't think it should be necessary any action for the admin to configure it. Currently there are some system default VAT templates that work more or less, but not always.
For example, I have created a customer with the billing address in the EU and an EU VAT and the cart still applied the VAT of the billing address (instead of 0%). Even if I switched between addresses or reloaded the page, it still charged a VAT. Then I disabled and enabled again the business checkbox and it changed to 0% VAT (with the same address).
On the other hand, I also tried with a customer with registration number but not VAT number, and the cart charged a 0% VAT instead of the national one. But later I tried with other customer and it applied the correct VAT.
I think the VAT calculation needs to be revised in order to be consistant and apply always the same VAT for the same address data.
Apart from that, it feels like the VAT settings are actually "copied" to user settings and I think they should be just calculated from Upmind side, so all the rules will be always updated without any user action (keeping the ability for the user to make own rules).
And finally, for EU VAT numbers, that would be a great feature to have if Upmind would be able to check if VAT number is correctly registered in VIES systems. Having an invoice with a 0% VAT and an invalid customer VAT number can be quite a headache in terms of accounting.
Another option would be if Upmind would just be able to connect to other accounting softwares for VAT calculation (for example Stripe Tax would be a great option, although fees could be very high when using Stripe Payments and Tax at the same time).