aspect ratio, image proportions

Dear community!

I have lived happily with version 7.0 for 10 years. Now, having made all my efforts and wanting to be progressive, I switched to version 7.1. And everything would be fine, I liked the Fluid engine and everything. Until I realized that the most important thing that an artist needs is impossible to do on version 7.1. It’s a barbaric violation of the image aspect ratio. Maintaining the aspect ratio is extremely important for a website selling paintings. It’s not just vertical, horizontal, and square - it’s precise proportions - it’s where the painting begins. Imagine that you enter the art hall of the Metropolitan Art Museum, and on the walls there are only square paintings, all of the same size(?)
I found a couple of incomplete hacks, but they are incomplete and turn the life of an artist with many paintings into hell.

I have two questions:
Can you suggest where there is a reliable tutorial or code (even paid)? 
When will Squarespace solve the problem? Apparently, no one has seriously thought about it yet? Should I start looking for a new home?

A working link to the page on your site will help us to see the issues. If required, How to Post a Forum Question provides guidance on how to provide a link.

I’m very sorry, I didn’t think about it. The fact is that the site is under construction. antonovart.com Well, here’s the password: "apaptra2023"  yes, and this is under this Link:  Art for sale