Select and checkbox workaround

Hi! First of all, I want to thank the creator for this wonderful plugin, it’s very useful. Now, on the subject at hand, can someone here help me how to create a workaround with the select tag.

I’m creating a restaurant WordPress site with an online reservation. For example.com/reservation, I created a contact form with drop-down menus. I enabled the multiple options but mobile users are only allowed to select one. As for the desktop, users have to hold the Ctrl button in order to have multiple selections which is annoying for users who are not tech-savvy. Is there a way where users can really select multiple options without holding the Ctrl button? I tried searching the net for answers but was unfortunate.

With that said, I tried using checkbox. It’s working as expected but there is a little problem with it, there are no limits on the checkboxes that can be check by users. Can someone help me with these too?

Thanks in advance xD