I now max out my & my wife's 401k every year, backdoor Roth IRAs, HSAs, and 529s and was reading about the Roth pipeline conversion from 401ks to Roth IRAs. I get the concept since I already backdoor Roth IRAs but I don't know when it makes sense to start making the conversion. I also have 401ks all over the place from multiple employments and I wouldn't mind getting the 2 that are not with my current employer out of the current companies. Same for my wife's 401k's.
Also, is it taxed when you convert from 401k to tIRA? Or is it exactly like a backdoor Roth where you only get taxed from tIRA -> Roth on any gains in that tiny window of a day or two?