Here's my take on this as a guy in his late 20s who is tall and very fit.
Bathroom or gym shirtless selfies that you post on tinder or whatever really just come across as kind of douchey. Whenever I see guys doing that in the gym locker room or out in the gym it just comes across as cringe worthy. This type of behavior is more feminine and not something that grown men do. Not that you are all that old, but at your age this would be even more the case.
Now, what could work in your favor would be showing off a fit body in a non posed type of manner. For instance, you shared a photo of you on some beach in Hawaii during a recent trip. Naturally you are going to be shirtless and it shows that you have a been living your life.
With all this said, women do in fact find fit men very attractive and any that say they aren't into that are lying to you. You may in fact intimidate insecure and/or fat women by flaunting a fit body, but at the end of the day you shouldn't want that anyway haha.