Sure, by the time they've decided to use a new thing, they are unlikely to change again soon, and if, at the time some team is evaluating a new system yours isn't on the market, you wont be considered.
So take a deep breath, stop sweating "first to market" startup tropes, build a good product and start thinking about how you're going to sell into this market instead that's probably a much bigger challenge than building the product in the first place.
There's no first mover advantage here; there's only a "most able to convince people to switch from 90's tech to 00's tech"-advantage.
FWIW We sold video interviewing software and decided to abandon recruitment because the market had low requirements for software quality / innovativeness and high requirements for stability and track records; which was the polar opposite of what we offered.
Additionally; ATS integration was paramount for all large players. ATS providers knew that and charged for it at levels only heavily funded companies could afford.