Agreed on the bad usability, but that's par for the course with most Electron apps. You get the laziest possible "stuffed a webpage in a window" UI. And maybe it's even a nice UI in some ways, but it's usually pretty clear that it's not native software.
Re: moving away from Electron, not as far as I know. They had a major update a year or so ago to make some big efficiency gains by not running a separate Electron instance for each organization, but the new version is still in Electron: https://slack.engineering/rebuilding-slack-on-the-desktop/
One can hope that they'll take the iPad version and make some improvements to let ARM Mac users get that instead, but currently they've chosen to disable downloading it from the Mac App Store.
God forbid you want to be in two Slack orgs at the same time, perhaps on different virtual desktops. Off to the browser version with you!