i like to think cryptids exist, but i doubt any of the supposed non-avian dinosaur cryptids exist. if the "pterosaur" cryptids exist, they're more likely to be birds or bats of either known or unknown species. i wouldn't be surprised if there's some really big bats we haven't discovered yet
i think cryptids are either undiscovered but otherwise mundane animals, misidentified known animals, or (in cases of things that are sufficiently weird/inexplicable enough) either completely made-up, or maybe actual supernatural beings. like, i think that some creatures native americans/first nations people believe in are possibly real, and i will not say the names of these creatures, mainly because native americans don't want their names to be said, but also because saying their names attracts their attention.
it should also say something that i'm open to supernatural things being real, but i find any conspiracy theory more convoluted than "the government has knowledge about UFOs and is covering it up" (either to keep people from panicking about aliens which may or may not exist, or to keep any top secret aircraft/spacecraft they're developing from becoming known), "there was more than one shooter assassinating jfk," "oil companies knew about climate change and instead of addressing it decided to spread lies about it not being real bc profits matter more to the greedy sociopaths running big oil than peoples' lives do" or "there is a concerted effort by fascist christians to subvert democracy and install a theocratic dictatorship with the explicit goal of murdering all my friends."
and the last two aren't even theories, they're just facts.