And no, it has nothing to do with your website being free. Google is a separate service from infinityfree and they don’t care whether you have free hosting or not. Again, read about the sitemap. It’s basically a file that shows google all the webpages you want them to index and instead of their traditional way (finding links to other web pages from one webpage, like a navigation page), they will go to all the webpages in the sitemap and index them.
They can be slow, just be patient (or check if you have any errors, submit it again and check if it’s submitted). I had no problem (once I worked out the errors) with google indexing all my pages, so either they slow, or you’re not submitting the sitemap in the wrong format or something else.
Just wait do not submit your Site map again and again, google cannot change priority of your site in indexing process.
At the end wait and start live test from site inspection feature on search console.