Eck, please don't do this. Think of this with any other language/framework. "Your app was written in C++ but I rewrote it in Arc because the code is way nicer. You're welcome." or "You used Java but that is a pain because it has to be compiled, so I rewrote it in PHP and now it's possible to make changes live on production servers."
There are many reasons a maintainer may not want to do that (eg, not knowing or wanting to learn the language/framework, having an ecosystem of plugins/branches that would be negatively affected, different opinions on what the project objectives are and how best to achieve them, etc). It's very hard as a maintainer to have to close a massive PR that someone put a lot of time into, and it's obviously a waste of time for someone to work on something that is ultimately rejected.
What you can do instead is open an issue and say "This is very memory-intensive because of Electron, are you open to addressing this? I'm willing to rewrite using <framework/language>."
You can also fork (or effectively just start a competing project) and become the maintainer of the new project. If you're not willing to do that, it's really not fair to expect someone else to -- as effectively with a massive PR you're basically asking them to take on maintenance of your code.