I can type about 15-20 wpm on a computer keyboard. I don’t think I’m doing anything wrong either, and yet I can help but suspect you have learned and practiced something I have not.
Maybe something similar has happened with your writing.
I grew up in the cursive age and I'm mostly incapable of writing well by hand. No decades of practice ever budged that needle.
Past that, I'm glad to see cursive go away; it is only legible from the people who are capable of doing it well.
I've been doing genealogy for some years now and I can't count the number of unreadable documents that would have been saved, had they been written in block. For each one, I am reminded that cursive begins with curse.
Maybe something similar has happened with your writing.