Indexing issus

I’ve been having an indexing issue for several days. Out of around 45,000 pages, about 38,000 were indexed. Due to a problem, only 18,000 are indexed now. I suspect it’s related to the sitemap, as it’s not submitted in Google Search Console or there might be an error with Cloudflare. Bing hasn’t indexed a single page for months — this issue should also be resolved.