Did you try the version from this page ?

• https://ftp.mozilla.org/pub/firefox/releases/114.0b3/win64/en-US/

On Windows if you download via the 'all' website then you may get a special version with a __MOZCUSTOM__ section that identifies your download location for telemetry purposes.

• https://searchfox.org/mozilla-beta/source/python/mozrelease/mozrelease/attribute_builds.py

The version modified this way obviously has a different SHA256 checksum

Right. https://ftp.mozilla.org/pub/firefox/releases/114.0b3/win64/en-US/ Indeed provide download which matches shasum from https://ftp.mozilla.org/pub/firefox/candidates/114.0b3-candidates/build1/SHA256SUMS

I was a little confused because couldn't identify download straight from here: https://www.mozilla.org/en-US/firefox/all/#product-desktop-developer

It worked with official edition though.