Is there a dictation app with no word or usage limit?

Yes. Cloud dictation apps commonly cap free tiers at a few thousand words and meter usage on paid tiers, because every word you dictate costs them cloud inference. Dicta transcribes on your own machine, so the marginal cost of an extra word is zero for us, and there is no word cap or fair-use throttle at any tier.

That applies to everyday dictation and to long-form transcription (a full recorded lecture or meeting), not just short snippets. See Dicta vs Aqua Voice and Dicta vs superwhisper for how their usage limits compare.