Yes i have checked similar posts. One 403 Error - Google Search Console - #8 by user7872 had the same exact similar issue.
He too couldn’t get google to crawl his site and also couldn’t submit the sitemap. Also when he disabled CF name servers google was able to crawl and he was able to fetch the sitemap.
Also to note is that other knwn bots seem to crawl succeessfully.
unfortunately he did not get a solution and he just had to give up using CF.
I really hope we resolve this coz i wanna use CF. I have already set some logic in my site that depends on CF rules.