Make characteristics required

-- HikaShop version -- : 6.5.1
-- Joomla version -- : 6.1.2

Hi,

I need to make some characteristics required to select and also display a text "Please select" instead of showing a value there.
I tried to add the "Please select" as an extra value of each characteristic but i don't want it to be selected as a value.

Also i have a lot of options in 4 characteristics in one product and the page load is very slow, is there another simpler way to do this?

Thank you