TL;DR: You don't understand how bandwidth is carved out; it is confusing, but unfortunately, you are limited to 120Hz.
The 4070 Ti can push 4 monitors at 4K 120Hz or 2 monitors at 4K 240Hz / 8K 60Hz
This is the first clue: the max bandwidth for all channels is 3.981 Gigapixels
However, the allocation is not as simple as using only what you want per monitor while keeping the rest in reserves for the other monitors. The hardware evenly distributes the bandwidth per monitor as they are powered.
Therefore, a 4 monitor config is only supported with up to 4K@120Hz per monitor, you can not borrow from one reserve to give to another which is what you are trying to do.
If you want to go higher than 120Hz on a single monitor, you have to limit yourself to 3 monitors or less. Even then, you might not be able to do it depending on the driver and what it actually supports in terms of 3 monitors.