Which demo for simple store

Hi again – I think I am out of my depth and need some advice.
I am trying to build a basic website ( https://izha.com.au ) using the “Online Shop” demo. But I am really lost and struggling.
My husband is helping as he built his website ( https://formatmyresume.com.au ) using the “Landing / Startup” demo but he too cannot make mine work as I would hope (he is also non technical). So my question is:

Should I just use the same demo “Landing/Startup” as him as I will only ever sell a couple of products? His website only sells one product (digital/service) and I think it looks pretty good.

Your collective advice so I can get my business up and running once and for all?

Really appreciate your advice (and any links to sites using your recommended demo). Thanks, thanks, thanks.