I cannot reccomend against Kiel, iar, and atollic enough. They are garbage ide's (can only do string based auto complete, no dark theme, very poor window management), yet still cost a small fortune if you want to go above 32KB of flash usage or whatever other the free versions do. They also have their version of a linker script which is even worse than normal linker scripts, and if you are forced to use their compiler then often it doesn't even handle c++11. Or if it does have c++, the auto complete doesn't.

Go for gcc or clang with cmake (or even just make) and use qt creator or visual studio code or others. You will get cmake based auto complete, access to a proper IDE color scheme of your choice, get to use your own compiler (clang, gcc, etc), and it's much more flexible. And for debugging be able to use a much more capable ozone from segger, or even gdb enabled backend in qt creator or clion.

My work flow for example is cmake and gcc regarding tooling, qt creator or visual studio code which works with cmake to give me proper context aware auto complete, and clang-tidy as a linter running in the background. I am incredibly productive with this, and am able to make use of c++17's features to go for true zero cost abstractions, while shifting checks from runtime to the compiler via types and static asserts and whatnot.

Plus, this is far more portable. No longer having to worry about project files working across diffirent versions of keil (this bit me in the ass at my last company). It's just a simple text file.

With regards to tooling, if you like Visual Studio and are working on ARM processors, I can't recommend VisualGDB enough: https://visualgdb.com/

It's not free ($189), but it removes so much friction from the embedded development process.

I'm not affiliated with the company, just a happy customer.

So does GCC!