Heading tags for accessibility and impact on SEO

Hey you all!

I am here again with some guidance needed from you all.

While reviewing for accessibility-related issues, I raised my concern about
not having some heading attributes to some of the section headings which is
a must for accessibility. To that-   the other team replied that it is
removed intentionally for SEO reasons. They are looking for a solution
where even less important heading attributes like h3, and h4 can be avoided
while still meeting the accessibility compliance requirements.

1. Per my understanding, heading attributes  -specifying in HTML formats
like H1, and H2 is a must and we should implement it that way only. am I
correct here?

2. What other solution can be implemented which will make both WCAG 2.1 AA
and SEO happy?

Please guide.

And thank you as always for the support this group provides.

Regards
~ Kiran