What are my options for a thumb trackball for gaming?

I have used the Logitech M570 for years, however when I compare the DPI on it to normal modern gaming mice it seems lackluster. I also would like to use all my fingers for buttons in games that require a lot of different keys and I can’t help but feel they are wasted on the two + scroll that the mouse has.

I have also ordered a Japanese mouse call the Elcom M-XT1URBK with the promise of more DPI options and more buttons. Although I did like the way it was wired and I do currently use it I found three issues that lead me to look for other options:

• The extra button just slows down the trackball so movement can allows for more precision but is hard-coded and can not be key-bound.
• The mouse acts like it has mouse acceleration that makes gaming harder. (I may be wrong about this but so far it looks like it.)
• The size is small I find my hands cramping after a few matches of an intense game (about an hours use). My older “M570” mouse did not do this.

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What are my options for a thumb trackball for gaming (aside from the two listed)?