Will breaking all the titles on a page boost SEO in anyway?

So, I have this suggestion by a client – asking me to break the title on every section into two tags. They want to replace <h*> tag with a combination of <h*> and <p> tag.

So according to them I should rewrite <h1>Hello World</h1> as <p>Hello </p><h1>World</h1>, but somewhere it can even go like this <p>Hello</p><h*>World</h*><p>there</p>

I’m trying to understand what negative impact it could have?

One accessibility concern I know is – that it is causing problems with some Screen Reader tools – as the reading agent only reads a bit of title and stops, then I need to focus on another word and then reads.

<div class="mixHeading">    <h1 data-fontsize="45" data-lineheight="63">SEO Experts</h1>    <p>to Maximize the Impact of Web Content</p> </div> 

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