Do you mean flip as in buy one new and turn around and sell it or just sell ones you already own? Selling a watch isn't "flipping".
That said, the hype watches from Rolex/PP/AP/VC are definitely down already and seems like they'll continue dropping. There's also a softening in the watch market as a whole (due to US/World events), but less so for the watches that aren't multiples of retail. Right now its mostly impacting grey market dealers who overextended based on the expectation that prices would continue to rise, as well as idiots paying those crazy prices (although they don't have to sell). I imagine if this continues to head down over an extended period of time, you'll see a LOT fewer fly by night grey market watch shops. For those with liquidity and/or the ability to weather the storm, it might be an opportunity.
I still like independent brands with extremely low production. They aren't as liquid because they aren't well known, but there are so few available it doesn't take much demand. Just a month ago, Czapek announced they were halting orders on the Antarctique de Drake for a year and orders placed prior were only guaranteed to arrive by EOY 2024. Moser prices have gone up slightly since the beginning of the year and remain steady. I anticipate an announcement with Moser and a non-watch brand this month which may generate some excitement. Other independents like Parmagiani Fleurier also remain quite popular.
There are a lot more people who can buy a luxury watch when the price is going up than the number of people who can buy a luxury watch when the prices aren't going up. This will be a big, and well-needed shakeup and hopefully return some sanity to the secondary market. For the longterm, that's a good thing. The pre-owned market is still going to grow over the coming years - but the craziness of the past 18-24 months is unsustainable.