I wanted to use the header of my website that has a time counter attached to your maintenance but it shows on the homepage, and not on the product page and shop page. time counter in your maintenance page
Please try recreating the header banner HTML Block that you added and clear cache and check back.
If the problem still continues then deactivate all the third party plugins and tell me with the permissions to debug then we will troubleshoot with the theme plugins.
Your header banner field contains the HTML block ID and this HTML contains the countdown widget only, how do you display other content in the Header banner?
Try to add everything in one HTML block.
I have checked on our testing site, the countdown appears on all the pages in the header baner.