I agree Bulgaria has better banking options, although it seems your problems are because of the lack of substance in Estonia.
Indeed Estonian tax authorities can bombard your mailbox. It's their way of working. Instead of them starting a tax audit (which they rarely do) they kindly send you emails with inquiries. With tax audits, you are obliged to send all your documents within 5 days.
If you pay someone a salary that is below the market rate they see a higher risk that you are paying an undeclared (“envelope”) wage, so it kind of triggers them to conduct a tax audit or send you an inquiry, but no way they can determine the amount of salary you pay.
But it is not mandatory to pay a salary if you open a company in Estonia, right? I can use the company to invoice clients in the EU, for example, and then from there I make a service invoice to my LLC in the USA. From this LLC, I can use it for my expenses as salary.