"Theia is designed from the ground to run on Desktop and Cloud" Which means it's an Electron app - which means between this and Chrome, it sucks down tons of ram and processing power. Really hoping Nova from panic.com is as good as it looks / native MacOS app.
This Electron-bashing is getting rather old - it's possible to write crappy code on any platform. Yes, some Electron apps are resource hogs, but many are not. VS Code is a perfect example of how Electron can enable development of a performant , cross-platform IDE.
VS Code is unable to scroll text without dropping frames on my MBP 2013. Meanwhile even Xcode is (graphically) smooth as butter.