Canonical / alternate setup

Hi everyone,

<link rel="canonical" href="example.com/tr-tr">
<link rel="alternate" hreflang="tr-TR" href="example.com/tr-tr/">
<link rel="alternate" hreflang="x-default" href="example.com">

I've been trying this setup for a week, but Google always selects the main page as a canonical and doesn't even index the tr-TR alternate. I've wasted various credits on different instant indexers and it won't index at all. Do you know what I might be doing wrong? The pages are perfect duplicates, like my competitors are doing.

(Avoid any BS comment regarding Google Guidelines; this is black-hat SEO.)

I posted a thread about the same issue.
https://www.blackhatworld.com/seo/spammy-google-selected-canonical-in-search-console.1840297/

Google is conserving crawl budget and avoiding indexing similar content. You should create structural changes to the page and avoid pointing to same set of URLs from both home pages. Your chances of indexing increase with the diversity in pages.