Is Martial Arts ability inherently bounded by the anatomy we are born with?
Not so much by height alone in absolute terms (i.e. real unarmed life-and-death fights), but within your own style - with their rules, techniques and training methods, conventional tactics etc. - it might be more or less important.
If you feel more comfortable with the challenge of fighting other people of similar overall build, you could look for styles where the tournaments are split into weight divisions: if someone's still taller at least it probably means you heave a strength advantage. You could still enter the next weight division up if you want greater challenge, without it being totally overwhelming. As you get used to that you may be able to work your way back to open weight tournaments, if you think that helps you prepare for actual fights against much larger opponents and that's your priority.
Key skills include closing the gap suddenly, "trapping" - where you block the opponent's limbs across their own body restricting their further movement, getting blind side advantage (behind the line of their shoulders - though in an artificial rule set their may be limitations on the strikes you can perform from there), and "centre line" concepts such as wing chun's where you block the taller opponent's efforts to bring their limbs in from the sides and press forward owning the centre.
I personally find watching video of fights in slow motion useful to clearly see why/how the fight unraveled as they do, and I suggest you patiently study video of your own fights or sparring sessions, and other fights where there's a height discrepancy, particularly if the shorter fighter dominates. If there's someone you have trouble defeating in the dojo - watch how someone else picks them apart and try to apply some of the same tactics, or other tactics to exploit the same weaknesses.
Are there any short but exceptionally good martial artists I can draw inspiration from?
Kenji Midori, Kancho (President) of Shin Kyokushin karate, is 165cm tall and won the 5th World Tournament for Kyokushin, back before the founder Mas Oyama died and the organisations split. In that final he fought Akira Masuda, 177cm tall, though he fought taller opponents at other times. You'll find plenty of online video of his fights, as well as demonstrations of kata and breaking. That said, fighting without punching to the head could be considered somewhat of an artificial equaliser between heights, as having your head in arms reach isn't so dangerous, but then kyokushin allows downward elbows to the collarbone/shoulder, and knees and kicks to the head, with no protective gear.
