Need Help with IR interference from different devices

I got my AC unit out for the summer, and unfortunately some of the IR codes are the same as the remote for my HDMI switch. HDMI 3 Turns on the AC, which is annoying (and funny).

Now the HDMI switch has a port for an IR extender, so I have 2 questions and am open better solutions.

My idea was to buy a cheap IR sender with a port for an external blaster / transmitter, and run a cable straight from the IR Sender to the HDMI switch.

Question 1. Will that work?

Question 2. is there a cheap IR sender with a port for an external blaster? the broadlink stuff doesn’t have any external ports, and the harmony hub is overkill and discontinued anyway

The HDMI Matrix is an EZcool 4x2 EZ-MX42HS

It does have an RS232 port, but I have no idea what i am doing there.