Honestly virtually all verification mail lands in spam on most free providers.
And it’s no wonder. Try running your own server sending these mails before you judge. My company needs to put a lot of work into this.
Why?
Because spam is rampant. So in return, anti-spam filters are extremely strict. And there’s dozens and dozens and dozens of hoops to jump, and holding one leg just a tiny bit wrong immediately gets you spam filtered everywhere.
You might think “This sucks, just don’t block as much!”, but you’re not seeing the thousands of mails that never even reach your spam folder because the server-to-server traffic already blocks them and they don’t make it through that. The percentage blocked is crazy. Spam is that bad.