I’ve used both F# and Scala professionally. Scala for a much shorter time.
Under most circumstances you will not actually be making a choice between them, because F# is .NET and Scala is JVM. You, or the people who made the choice for you, likely picked the platform first.
Hypothetically, if you ignore the platform, which most don’t, then I’d say whether you like F# or Scala more depends on whether you prefer a relatively simple minimalistic language or a language with lots of features. If you are the person who writes “X language feature or GTFO”, you will likely hate F# and love Scala. If you like concise straightforward functional code and like to get things done, you might prefer F# rather than Scala.
IDE experience with either wasn’t perfect for me. My Scala (2.13) experience with JetBrains tooling was absolutely horrible (the IDE simply didn’t agree with the compiler on our 6 figure LOC codebase) so I switched to using VS Code with Metals, which seemed to better (but not 100%) agree with the actual compiler and gave an Ok experience. I’ve programmed in F# with Emacs (which I usually prefer), VS Code, JetBrains, and Visual Studio. None of these give perfect experience, but have been Ok. Programming Scala without an IDE is not something I’d recommend (various features of Scala, like implicits, zero-argument functions, and by-name parameters, pretty much require you to have an IDE, because code (control flow) is not understandable locally), but I have found programming in F# (and Standard ML and OCaml (both of which I’ve used professionally)) productive even without an IDE (just syntax highlighting and grep).
I don’t understand the problem some people have with ordering files in F#. If you don’t mind lexically ordering your definitions in OCaml, then ordering files in F# shouldn’t be a problem to you and you might appreciate that it can make the code simpler and make the code easier to navigate and understand. In a project of any size the time you spend ordering files manually is absolutely insignificant. By contrast, in the Scala project I experienced professionally, there were internal “libraries” that had cyclic dependencies with application specific code and some people preferred top-down and others bottom-up ordering for definitions and some probably didn’t even think about the ordering.
If I were starting a project on JVM, I’d likely seriously consider Kotlin (which I have also used professionally) before Scala. In particular, if I knew that co-workers on the project would not be hard-core FPers, I’d likely recommend Kotlin rather than Scala. On .NET C# (which I’ve also used professionally) is orders of magnitude more popular than F#, but I definitely prefer F# as a language.