Wireless Keyboard

if it was me then I would test the keyboard with another computer mac or pc would make no difference

and or test another keyboard with the mac to verify the keyboard being the culprit

you can also try making a new test user and check if the issue is with that user too when you login

and or iMac SMC and PRAM reset - Apple Community

Make sure Mouse Keys aren't enabled.

Control the pointer using Mouse Keys on Mac - Apple Support

Jlpgot5 wrote:

There are some keys on my key board that will not work.

If 789uiojkl, hit Option 5 times and make sure Mouse Keys is turned OFF.