Never been a friend of these almost mandantory things to say, like "how are you" when meeting someone, especially when the common idea is that nobody expects an actual answer to that, but just a returned "how are you" back, when someone greets me with a "how are you", I usually just reply with a "hi".
Same thing in emails, I leave these formalities completely away by now, no hi or hello or dear or whatever on start, not addressing the one by name, nor any regards or whatever underneath, not even signing my name.
By my experience nobody cares, whether I write a hello on top or regards underneath or just write the core message of what I have to say while the address the email comes from contains my name anyway.
If the content of the mail is in a friendly tone that's good enough for about anyone.
I'm aware most businesses have the top and bottom of their emails prewritten, so all the emails I'm getting from them begin with "Dear ..." and end with "Best regards" or something like that, but I couldn't care less, I look into the text of the mail and if that appears to be just prewritten pieces of text copied and pasted together, I mind that, no matter how formal the top and bottom of the email looks.
I even have the experience, when I write an email without formalities on top and bottom, as long as the answer is a real one someone typed, they happily leave the formalities away as well and the content of the text I then receive is usually much friendlier than in emails with formal top and bottom.
No, you're doing it wrong. Any written communication in business requires a salutation and a signature. There's nothing familiar, kind or cutesy about it. The salutation is to make clear who the message is for. And the signature shows who it's from. If your email to me doesn't address who it's intended for, I delete it without reading it. I don't have time for nonsense.
"All the best" or "Best wishes" or whatever. It's meaningless so I just type anything. Any manager who cares about things like that isn't good at their job.
In Hong Kong, I had a manager who insisted that we add people's email addresses in the "To" line in order of decreasing seniority. I'm usually tolerant of cultural differences but I just laughed at that. Life's too short.