There are a few github repos with promising name related to AURIX TC3 development. I've been pulling them and trying to build tools to see what I can use.
A lot of them are pretty dependent on the environment and sometimes won't build. Or won't run. But I managed to craft a version of OpenOCD which will work with a mini-wiggler and allow me to do basic work on a TC3 development board.
I'll post a recipe shortly. Given a modern day linux installation (Ubuntu 22.04) and a mini-wiggler USB dongle and a dev board it appears to be possible to do real development.
At some point I'd like to do the same with a TC4, but I suspect getting a TC4 dev board will not be an easy trick. We'll see. I grew fond of theTC4 - it's a very powerful chip.