Niche language, but try out PureBasic.

Its IDE is based on Scintilla. And it is very fast, even on an ancient PC it runs. It is specific for the programming language.

And here some advantages it has compared to a simple text editor:

• Autocomplete of all functions and many API functions of the OS
• Hints about parameters
• F1 Help for all functions by just placing the cursor on them
• Jumping to errors in the code
• Automatic backups of all the progress of your codes, no problem to backtrace even if you forgot to save or commit.
• Manage Projects (Groups of source codes and different targets)
• Well integrated debugger

I agree with you in many points. Most other IDEs I am forced to work with are horribly slow. Especially those which rely on electron. Sometimes they lack features every basic editor has by now.

This is to say: Good IDEs can exist and are a great benefit for the programmer. But modern IDEs often chase keyword features and use complex and bloated frameworks to achieve them. Sometimes even forgetting to add basic features which made IDEs a thing initially. An IDE should take almost no time to setup to your needs and should not hinder with complex operations which take seconds to run, it should only support in code creation and aim to make features like autocomplete show suggestions in milliseconds.