Sent difficult question - got helpful response
I run an online Job Board for the region of Salzburg and use the Assembly API for transcribing audio data as well as for generating text proposals for my customers. Former this was all on B2B Level, but now I am extending my services on applicants, e.g. we have GDPR-relevant topics from now on. I have to grant to my customers that their given data is not further used in another way than the originally intention. Michelle from the assemblyai support Team responded quick to my individual support request and give competent feedback to all the (sometimes very detailed) questions. After all I can say, that this company is capable to treat personal data correctly in the meaning of GDPR, even abroad the area of EU-member-countries. Maximum respect.