Sitemap Checker
Use this tool to check the validity of your sitemap. You can either provide the URL of the sitemap or copy-paste the sitemap content directly.
Why do you Need to Validate your Sitemaps?
With the volume of new pages being added to the web, you need to help the search engines to get a hold of your content. And though the spiders are supposed to discover new content, crawling budget limitations may make your content hard to find, especially for new sites
This means that you NEED to submit your XML sitemap to Google and others, so you may it easier for you to be found. But there is a little catch: the sitemap needs to be valid XML code, and it fails to validate, Google simply WILL NOT PROCESS IT.
If your sitemap is found to be invalid, you will get a message in the Google Search Console saying that your sitemap is broken, and that you need to fix it. And they will not crawl it until you fix it. And even if you fix it, there is no guarantees in terms of when they will give it another try.

How to Avoid Issues with Crawling Budget?
The search engines have limited crawling resources and without a doubt they will prioritize websites they trust. Those are websites that post quality content on a frequent basis.
So, your path to increase your chances of not being subject to a limited or zero crawling budget is to deliver great content, and do it frequently, giving a strong signal you are a trustable site, even if your site is new.