One reason you might have trouble with nail clippers is that they seem to be designed more for narrow fingers on women’s hands. If you have wide fingers, you might have more luck with toenail clippers. They are wider and longer. You can get more leverage with them. And because the cutter is curved, it’s easier to get your cut nails to have a curve to them rather than with the straight edge of a diagonal cutter.
Every 8 weeks a podiatric nurse comes to our place and does my wife’s and my toenails. He mostly uses a dremel, although he does a final trim with a cutter.
You could try hoof trimmers.
I’ve used toenail clippers for my fingernails for decades. The quick at the end of the finger is almost straight across and the smaller radius curve of the former didn’t suit them while the larger radius of the latter did. For years I wondered why fingernail clippers were made that way until I had lessons in massage and looked closely at a wide variety of other people’s nails.