Live Feed setup question, multiple cameras, mixer, wireless wifi connection

I am looking into building a live feed system. I would like to provide live feed for online events, weddings, workshops.

I would like to have 2-3 cameras to record the event. I am thinking
about attaching a wireless transmitter to the cameras to send the signal
to a live feed video mixer. I would like to switch back and forth
between cameras signal is broadcasted to the online viewers.

How would you do this? What king of DSLR/mirrorless HDMI transmitter you
would use from the camera to the video mixer. What kind of solutions
there are to switch back and forth between cameras? Thanks so much!