From your screenshot of Ventoy, it appears you have successfully written mint 21 to the usb, to get it to install you must make sure you do not have windows quick-start or secure boot enabled, switch the machine off, put the usb in the slot, switch on whilst tickling the short boot key, if you do it right it will open the short boot menu, look down the list for the usb and open, it should then start to install.. READ MY HOW DO I GUIDE first, it is written with minimal technospeak and it has a link to find your short boot key,