I've done my own digging on specific kink dating app for BDSM and come up short. Half the frustration disappears once you report problems early instead of blocking quietly, which is the whole problem with kink apps. The bdsm angle is worse, because the platform buries the cancellation flow, and how many first messages actually land suffers for it.
If bdsm kink is your priority, the deciding factor is the number of live users, speaking only for my own city. Applied to bdsm apps, what decides it is the time it takes to get a first reply, not the size of the ad budget.
Same story on bdsm kink: the platform shows dormant accounts as active, and you only notice once you have spent a few evenings on it. The reason specific kink dating app for BDSM keeps coming up is simple: the amount of recycled content is the number worth watching, not how many photos people post. If you have been through the bdsm version of this, I would rather hear the unglamorous account.