Recommendations for iMac replacement keyboard

FWIW, I have been using Logitech keyboards with my Macs and PCs for years now and never regretted doing so.

I am currently using the MX Master S mouse and MX Keys S keyboard. I use this particular keyboard, as again, I use it for both Macs and PCs. Logitech also has the MX Keys S for Mac keyboard if you only intend to use it for Macs.

What I really like about these devices is that they work either with Bluetooth or with Logitech's Logi Bolt USB receiver. I use the latter as it allows easy switching between my devices.

If you'd like one with backlit keys consider the Matias Backlit Wireless Keyboard. I have an eye condition where I have to have the room lites down very low or off and with the Dark Mode on my Mac. This keyboard works beautifully with my Mini M4 and with my previous Intel 2017 27" iMac. I can see the key designations in the dark or low light.

Just some food for thought.

Before that I used the Apple Magic Keyboard with the Numbers Keypad.

I recommend that you shop at macsales.com for a keyboard that suits your needs. The reason I recommend this vendor is because they specialize in Macs and everything they sell has been well tested so you know it works. You have a LOT of options available to you, I'm sure you will find a keyboard you really like!

all usb and bluetooth keyboards works really

I've used various Microsoft natural keyboards and logitech keyboards all both in wired or wireless versions.

Just to add, Logitech also makes backlit keyboards.