I don't have an issue compiling for the C6.
I'm not sure why others are getting issues?
A few things to try.
1) Make sure that target is set correctly. Use 'idf.py set-target esp32c6' and if it doesn't complete successfully try deleting the 'build' directory.
2) I'm actually using v5.5 of the toolset - but 5.3 'should' work as well.
3) I don't use the usual Flowcode setup or batch file (read the instructions is usually well down the list

of things to do) So I have used the default espressif installer (and have several frameworks installed) - I use the batch file at
https://www.flowcode.co.uk/forums/viewt ... 557#p18557 - the drawback is that I need to alter it to use the correct COM port each time I plug a new board in (there is surely a way around this)
The toolset isn't keen on changing targets - and needs a complete rebuild each time you do so - FC's default batch neatly uses a pre-built directory for compilation (which speeds up compilation) - however doesn't play as nicely with espressif components. The batch I use uses a separate directory for each project - I found that the 'setting up environment' takes more time on my PC - so it's a bit quicker (just does it once for compile / upload rather than twice) after the first compile.
4) Try compiling from the command line (framework/export then idf.py build - need to find the directory 'framework')
Stefan - output seems to imply it can't find the compiler??
Jorgen - what errors do you get
Grout1 - can you post the compiler message?
Martin