This only works if you create an Estonian holding company with Bulgaria daughter company, or when Estonia company registers a branch in Bulgaria.Regarding creating substance in Bulgaria for Estonian resident owned company in Bulgaria. Would you recommend using a Bulgarian or some other nationality nominee director / or second nominee director in addition to Estonian resident who is the owner and director of the Bulgarian company.
Its worth noting that a branch representative has less direct financial liability, compared to a director. This could make it easier to find a reliable person. If you want a local bank account then a local resident would help. Also foreign branches don't require a local bank account which at least was the case with local companies.