I am afraid this will perhaps sound a bit harsh. I am daily IntelliJ user and in spite of all shortcomings I still consider IDEA IDE to be the best for my purpose. That said, the image conveyed by the words above does not reflect the reality which is: Scala 3 support is seriously lacking in IntelliJ, esp. the highlighting and type inference is inferior compared to excellent Scala 2 support I have been used to.
Besides of named tuples there are opaque types, extensions and givens, which are older and more fundamental features, in my opinion. I have reported more than 10 issues regarding those features - most of them cause my project sources being significantly red.
I understand this takes a lot of effort and I do not expect this to be solved immediately, I understand the JetBrains team may have different priorities, but at least I would like the problem to be acknowledged.
I do not pretend to know the solution, but acting like a problem does not exist is certainly not a solution.
Recent language changes have been making their way into IntelliJ relatively promptly
For the record: all those issues I have listed in that post regarding opaque types (which are here since Scala 3.0.0) are still open. Most often the issues are in some combination of opaque types with extensions, implicits or givens.
Good news: two of those issues are fixed now - the fixes are published in a nightly build now and if I am not mistaken, the will be available in the 2025.1 release.
This makes my project mostly green - there are still a few cases where the resolution is not perfect, but they are just a few, generally the project is workable for me now, which is great progress.