Not sure how you've done this - perhaps the different model allows you to do this (I have an older TH-42PX600), but I don't have a button which can change the input source to HDMI. However, I did have issues with the inputs where I had to program the remote to send different colour buttons after it had turned on the TV to ensure I got the right source. I've literally just updated the remote today and it updated the device for my TV. Unfortunately it stuffed this up a bit and I've just had to reconfigure every Activity which used the TV device! Now that's done though, it looks like they've sorted these issues by programming in these button presses which is nice for new users!
Given you have this button though, one possible way could be a sequence i.e. go into the Customise Buttons section of your Activity, and click Add Sequence. To change to AV1, set the first sequence to press the button which goes to your HDMI input, then the second in the sequence to press the Red button (or any colour button which brings up the on screen display), then the third button to press Red again to go to the first menu in the display, and then a fourth button press of Red again which should select AV1. For component, do the same except first button goes to HDMI, second presses Red (or any colour button to bring up the display) and then third button is Yellow to select Component.
This is all assuming your model is the same as mine in choosing inputs of course!