نقش و معنای But

عالی بود متشکرم

Hi.

The first instance is a coordinating conjunction. The second one just refers to the first one  and here is used as a noun.

Overall, the  speaker is trying to say something that contrasts what has been said before; however, he/she is trying to convey that the overall meaning of the additional comment (what he/she is going to say) is not going to be negative.

معنی نزدیک:

اما، همین حالا بگم این اما، امای بدی نیست(معنیش منفی نیست)...