I don't know about the specifics of Electron but there are some tools to create MacOS installer packages on Linux[1]. I've done this to distribute a game written in the Renpy engine, it's a bit convoluted but it works. I'm not sure if app notarization is possible though (probably not), it's been a while since I dealt with this stuff and notarization wasn't required at the time.

[1] https://gist.github.com/SchizoDuckie/2a1a1cc71284e6463b9a