It is difficult to estimate the potential of a niche new gTLD project but "comparing" with existing extensions from the first Round of new gTLDs is an excellent approach.
Check the numbers !
New gTLD reports are monthly domain name registration volumes' captures according to specific groups, businesses or industries. On the last day of each month, we take a snapshot of these numbers so one can see if they increase or decrease for a month to the other.
Check the monthly reports here (next report to be published will be March 2025).