To be fair, aqua computer controllers start at 49.90€ for QUADRO with 4x PWM channels.
Yeah. The Quadro is more than that where I am, as is the competition. Comparatively, all the ITX or (m)ATX motherboards I've looked at recently have had 4–6 PWM fan headers.
Going from an MSI Z490 to ASUS Z690, I think MSI had better fan control.
Judging by the ASUS B550 board I'm working with at the moment, it wouldn't be hard. ASUS FanXpert 4 is the current version but the board, which is in current production, is locked to FanXpert 2+ and isn't updateable (unless there's some sort of jailbreak I haven't been able to find, anyways). The only curve inputs are a CPU temperature—ASUS doesn't document which temperature it is but I suspect it's the average of all of the cores—and a motherboard temperature at some undocumented location that's pretty useless since it barely changes. The curves themselves have only minimum, middle, and maximum points, the poor mouse response in the BIOS makes positioning them tedious, and I found it trivial to manually improve on the auto fan tuning and benchmarking. Can't comment on FanXpert 4 directly but, in ASUS's documentation, there aren't any obvious differences from 2+.
What ASUS offers here is functionally adequate in an entry level sort of way. Given the diversity of workloads I'm a bit confused why it isn't the default to sense GPU, CPU, VRM, RAM, and M.2 temperatures and have the relevant fan RPMs respond based on whatever's running hot. I'm left with the feeling ASUS is just doing the minimum to tick their marketing checkbox and isn't thinking much about customers.
So +1 for FanControl from me.