32-bit color depth in Windows properties - how is it?

Question

Monitors

Somewhere you can read that 32 bits is 24 bits + 8 bits for transparency, but there can be no transparency in the monitor (I won’t see what’s behind the monitor). In general, I would like to know what exactly Windows does with such a color depth.
PS. I understand that in the monitor itself, the number of colors in the monitor can also be limited. However, if the monitor is converting colors, then it makes sense to give it a higher depth - this will reduce the loss of accuracy after conversion. But at the same time, 32 bits still remains incomprehensible - Windows cannot transmit 10.66 bits per channel. In the worst case, 10 bits per channel, but then why do we need the remaining 2 bits? In general, it is interesting how exactly these 32 bits work.