Transcoding From Lossy Codecs to OPUS (Lossy to Lossy), Which Bit Rate should I choose to achieve Audio Transparency/Minimal Loss in Audible Quality?

So I have all sorts of lossy audio files (from MP3s to Vorbis, AACs and even OPUS) and I would like to edit them in Audacity. Once the editing is done I would like to Export as OPUS (I understand there will be Generation Loss, I don’t mind so long as the audible diference between the original file and the transcoded one is minimal or almost imperceptible).

My question is, Which Bit Rate should I choose in order to achieve minimal audible loss in quality? Should I choose the same Bit Rate as the imported file? Should I choose 128 kbps VBR, since it achieves Audio Transparency? Or should I choose a higher Bit Rate than the imported file?

Thanks in advance.