Try rectangle if you’re on mac. It’s a window manager and you can config hot keys to move windows around. For example I keep my large monitor split in 3, with a window in each third.
I know it’s not exactly what you asked, but prob the best you can achieve.
If you want to try to roll your own web solution, you can try to create a page with multiple iframes. The catch is that sites control whether they can be embedded or not into an iframe and for security reasons they often disable that (search clickjacking if you want to read more). So, I’m a bit pessimistic this will work.