Hi Andile,
Pierre already summarized some alternatives (like Partiels and the ASAP plugin suite.) You can of course use virtual machines to run any pre-Catalina macOS in order to run AudioSculpt. As an example, I’ve been running AudioSculpt (3.4.6) with VMware’s free Fusion Player for a few years now. It’s easy to setup and I’ve never run into any issues with it.
All the best,
António