seo – why aren't new web pages and sitemap crawled?

We recently migrated our website by maintaining some old pages (URLs) with new pages added to the site. We submit the sitemap in the Google search console, but we see that we have tracking issues on most of the pages.

We have tried to manually force the index of all the pages of the website in the Google search console, but the same pages show the status "not crawled" in 24 hours. We understand that this is really bad for SEO.

Please advise how we can solve this.

Thank you.