Searching for my perfect rollaboard soft side carryon suitcase!

I am having trouble finding my perfect suitcase. I wonder if you bag lovers can help me find it!! I have some specifications:

1. Must be rollaboard (2 wheeled) carryon size.

2. SOFT sided bag. May have internal framing or not, but no hard plastic shells.

3. One single internal compartment. I do not need a bunch of fussy internal pockets, mesh, or zips- I have my own organizers I like to use. I just want one big compartment.

4. Expandable is a plus but not required.

5. Ideally under $300 but I'll go up to under $500 if necessary.