Talk to your Unitronic dealer about credit of your existing Uni tune going towards a different tune. They may have an upgrade-path.
Or sell your chipped ECM to recoup some of the investment and get a stock ECM to put the new tune on.
Your AEB engine is running the Me5 engine management system. Upgrading to the AWM wideband Me7 system is more involved than just plugging in a newer ECM. You'd need to also upgrade the engine bay wiring harness and all the sensors. Even if you do this, you're still capped by the limitations of the stock K03 turbo you have. Your KO3 is your main limiting factor at this point.