I used to have two Type Matrix boards long time ago. It got me into thinking about more ergonomic layouts and taught me first Dvorak and later Colemak. I agree with others’ comments about poor longevity. I also find that it’s not a very ergonomic layout in hindsight.
Learning how to clone this layout in a custom mechanical keyboard is like jumping into the deep end. There may be other ways. E.g. get an XD75 or ID75 and make a layout that’s “close enough”. That takes PCB design and lots of firmware hacking out of the equation. But you’d still learn about different switches, layers, thumb keys, maybe home-row-mods if you want and ease you into more possibilities of firmware hacking. You may find a more ergonomic or efficient layout than the Type Matrix that way, as well.