Hi @Yakiin, you need to put the same exact tags on all sites, so from what I can see you should put this in the header of every site:
<link rel="alternate" hreflang="x-default" href="https://makineagency.com" />
<link rel="alternate" hreflang="en" href="https://makineagency.com" />
<link rel="alternate" hreflang="de" href="https://makineagency.com/de" />
<link rel="alternate" hreflang="tr" href="https://makineajans.com" />
You don’t really need the regional part of the hreflang you had specified unless you really want it (mostly useful for when you have multiple variants of a language on your site), and as far as I know canonical is already provided by Webflow so you don’t need to include that either 
if anyone else knows better, feel free to correct me, though!
Here is a Help Center article from Google for more info (expand the “HTML tags” section):
Hope that helps! 