Poor quality subtitles translating among Portuguese and Spanish

We are preparing a conference event for Easter with the participation of Spanish and Portuguese speaking people. We want to translate in real time the speaker to the opposite language, i.e. a Spanish speaker to Portuguese and a Portuguese speaker to Spanish using Zoom captions with translation. We made several tests but we got results with very poor quality. It seems like Zoom does not understand well Portuguese (from Portugal people at least) and then the translation is frequently clueless. I've tested also using YouTube videos with caption enabled and comparing with Zoom captions in the speaker language, without translation. It seems that Zoom understand Spanish pretty well, but it does not understand Portuguese with an acceptable precision.

I'm using Zoom client 6.4.3 on Linux Mint.

Is there something that we can do to improve captions quality besides providing good sound?
Do I need to use a third party tool for this job? Please, can you help me? I need a quick solution. I already sent by email this question to customer care without an answer.

Thank you. Best regards.