help please… home page ranking instead of landing pages.

i created service page in my company's website that i want to rank for 3 word long keyword. onpage content is around 500 words with proper on-page as i included some LSI and other related words with content.

but after i published that page, it was not appearing in first 400 results so i added some more content 250 words in total 750 words.

now home page is ranking on somewhere b/w 200-250 result.

DA is 21 and home page PA is 33.

home page title contains that targeted keyword one…

help please… home page ranking instead of landing pages.