What is the opinion of Reddit about the
USB Switch Selector, KVM Switch for 2 PC Sharing 4 USB Devices, USB 2.0 Peripheral Box Hub for Keyboard, Mouse, Scanner, Printer?

It doesn’t work for the monitors but if you have trouble finding a KVM switch that handles what you need, I use this and its worked well for me:https://www.amazon.co.uk/gp/product/B07MNZ1FVS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I simply have my mac AND pc plugged into both monitors and just change source inputs, the benefit I get there though is I can independently switch one monitor to my mac, one to my PC and type away on one while letting the other do whatever.

Yes, you need a KVM switch. You can buy one on Amazon. Example:
Amazon