Sandstrip version 1.2 is its first release as a Universal App, superceding previous versions. It should run natively on both Intel and Apple Silicon Macs, on all versions of macOS from Sierra to Big Sur betas.
It’s now available from here: sandstrip12
from Downloads above, and from its Product Page (which gives full details about the app and its features).
If you’re running an Intel Mac and have any problems, please let me know. I’ll leave the Intel-only version 1.1 available on the Product Page in case you’d prefer to revert to that.