Traffic Stopped Since Dawn Theme Switching - is H1 not longer relevant?

Hi all,

few months ago switched my website jewelleryaf.com to Dawn theme,

since then the traffic is literally stopped! Upon some digging noticed the

tag on homepage is missed,

on contacting Shopify support they told me H1 is not longer relevant and Google now use different way to rank websites.

Do you agree H1 is not longer relevant and tell me what are the parameters Google now use and what i must do to improve my traffic and SEO ranking?

Also on Google search control my external links are messed up: few healthy websites are disappeared and the list show dodgy sounding websites such:

(rankcover.com -rankgarden.com - rankmanage.com - rankmood.com - rankvirus.com - rankitself.com -rankbenefit.com - rankbalance.com) as externally linked, is that cause of concern?

Any advice and feedback is welcomed, thanks