Sitemap issues on .fun domains

Built a CMS on a .fun domain, created sitemap file, and tried to send it to google through search console. But somehow google can't fetch it. Created another sitemap with other tools, and tried again, but this so called advanced search engine still couldn't fetch it. So, I created a subfolder and put sitemap into this folder, tried again, it didn't help.

Did some research, some fellows created threads on other sites, they had similar problem, because their projects were built on .fun domains.

I don't want to change the domain, because edited a lot of files, and it is quite good domain.

Any recommendations? Is this sitemap shit still important? After all, we aren't in mustache petes' era.

Just submit it and if it says it could not find it and you know that you submitted the right url then leave it, Google will pick it up later. This happens on some WordPress sites with .com to, it has nothing to do with the domain .fun it is a flaw from Google´s side.