Speaking of better in the old days, MSVC in the 90s had edit and continue, where you could stop in a debugger, change the source code and move the current breakpoint back and run it again. Even VBA had this 30 years ago, why cant I do in Python?
The visual IDEs of the 90s (MSVC, Borland Delphi, heck even MS Visual Basic) were way more tightly integrated, performant and usable than anything we have today, despite running on hardware with a fraction of the power. It seems so bizarre how much we've regressed.
MSVC is still here in 2025.
Microsoft QuickBasic does too, which I sometimes still use when programming on DOS (one of the reasons for this being what efaref mentioned about performance and usability and being regressed); and also has a "immediate mode" that you can enter BASIC commands and execute them; I think this is helpful.
.NET can hot reload during debugging session. Even that I never get used on this feature and just restarting debugging from scartch.
You can still do it in Java.
The best I can do is rebuild the class, then when the function runs next time you get the new code. Is that what you mean? Quarkus is good like this too.