My work Mac is a 16” MBP with an M1 Pro chip, the fans are almost always off. The reported concern is that, unlike the M1/M2 Max chips and all of the Pro variants, the M3 Max chips get hot enough under load to require high levels of fan cooling (and thermal throttling, as
@Canon Rumors Guy mentions).
Having said that, I strongly suspect the M4 Max won’t have the fan issue, at least not to the same degree. Apple tends to be pretty responsive to things like that (unlike some other manufacturers that are perhaps more relevant in the context of this forum

). Case in point, when going from the M1 to the M2, the base storage configuration used fewer NAND chips (one instead of two) and as a result the SSD read/write was slower on the M2 than the M1. The M3 base storage rectified that issue with a return to splitting the SSD across two chips.
I've read that the M4 vs M3 performance boost is not that big (there's a reason Apple compares the M4 to the M1 and Intel Macs), and I've also read the M4 has better thermal management...assuming there's more improvement on the thermal side than the performance side, that looks like the right direction for the fans.
Either way, decision time is getting close....