I think it's a really good start @sleek briar. I think the color choice and media as well as the effects are really good and well done.
My main critiques are about some effects and the copy of the site (if I saw the image correctly, it's a square image so you could crop it to a similar rectangular area within the header). I think you could try a stronger H1 and paragraph text. I got this as an example:
Personalized biokinetics, movement therapy, and holistic coaching to help you overcome pain, build strength, and feel at home in your body—online or in Standerton.```
I think you could shorten the text or adjust the structure in the section after the hero section since it's a lot of text and might be glossed over.
For the About Me section, the text has a Cross effect but it only covers about halfway through the screen. For it work best, you should use a layout similar to the image below with the grey cells.
I would also recommend trying a different preset for the Instagram feed as currently the two rows leaves some empty space.
Ultimately, I think asking yourself and the client what is the main goal of the site will help simplify the design and copy of the site to drive visitors to that goal. If it's the app, then it will be that; if it's bookings, focus on that.