VSCode keeps opening powershell on start even though Git Bash is set as default
Make sure you upgrade to vscode v1.60.1 - there is a fix in that point release for this issue.
The same thing was happening to me and the referred to fix in the Insiders' Build 05/14/2021 did in fact fix it for me. In the meantime, opening another terminal does always open git bash for me - but that is a pain.
I managed to find a workaround without using the Insider's Build that may work for some of you : I removed all profiles safe for the one I want, and reinstalled VS Code. Then it somehow started using the right terminal on startup. I don't know if this works without disabling all other profiles though.