I found my Edge Canary (updated every day) will stuck for seconds after launching on my macOS 10.15 Catalina Developer Preview 1.
Is it the macOS issue or Edge Canary? Can Microsoft developer look into this issue?
It can be hard to tell what the exact issue is when it comes to developer previews for MacOS.
I would try to download and install both browsers again, Dev Version 126.96.36.199, and Canary Version 188.8.131.52.
We can then see if both or at least one of the browsers works and then troubleshoot from there.