Using an iPad 13" Pro with Mac mini M4

I don't how many times I've tried to use the iPad with the Mac mini hoping to use the linked mouse and keyboard and I never seem to keep them connected. I purchased a brand new 8K HDMI to usb c Ugreen cable and the same thing keeps happening. I used think I was losing the keyboard mouse link, but recently I've gone back the my HDMI port with the Mac mini and the iPad looses connection so consequently the link for the mouse and keyboard are gone. If anyone has been successful in keeping this connection going I'd like them to share their secret. My second question is, why do I think I need it setup with the Mac mini? I think I'll just get another keyboard and mouse and run the iPad as a separate device. Any suggestions are welcome.