I’d maybe suggest playing around with a few FM softsynths first. it is a radically different method of making sound than the others on your list. The Digitone probably can make the sounds you want, but the route there could be a lot easier on other synths. On the other hand, the DTone can make sounds others can’t.
It’s possible you’d be better off with something like a Behringer Deepmind, or the Minilogue, or a 2nd-hand Nord Lead. Polyphonic, and you’ll learn a more ‘classic’ way of sound design. OTOH the Elektron sequencer lets you use the DTone as a complete groovebox in a way you can’t with the others. Maybe a used Analog 4 for a similar price as a DTone, if you want more of a classic analog synth sound with a great sequencer? The thing with Elektron is, you’ll spend as long getting to grips with the sequencer as you do learning how to operate the sound design parameters. Which is great, if you want a very good sequencer, but annoying for some people who don’t.
so I would take advantage of the wonderful opportunity software offers to dig a little deeper into FM vs subtractive synthesis, and if you find you really like the sound possibilities of FM then the DTone is probably your best option.