gradual ranking decrease of kws

my website is new.
today it's only got ahrefs rank 85 mill.
But I had few kws on 16 and 13 places, now they gone by 15 positioning down.

I m building links, press realises, nich blog comments

why do my kws experience that?

When ur website is new, dont focus on keywords ranking because they are fake

Google is still trying to determine where to put you.

Focus on adding content, builsing links, indexing

If its old website and you were holding position for some time then start losing it, then your backlinks are getting de-indexed

When a website is new then work is under progress continue the work then you can automatically see the ranking is up and stationary.
get back links from relevant good quality websites, after 2 to 4 months you can see the actual stationary rankings.
The search engine is not like to show the new website top of the world, hard good quality work is require.

Like you said that your website is new, so focus on posting as much content as possible. After a month or so, plan to build backlinks for it.