If there are shared folders on your network, and you need to access them from your Chromebook, there's a very easy method of doing so that doesn't involve installing third-party apps.
More helpful:
https://www.xda-developers.com/how-sideload-apps-chromebook/
Sometimes, an Android app that you want to install on your Chromebook may simply not be available on the Google Play Store. This could be either because it's incompatible, or because the app's developer has tagged it as such due to the experience on your device not being exactly how they prefer to present it....
[probably have to set up a Google profile on the Chromebook to log in and enable Android apps, but could you install the apps and use them under the guest login?]
The Chrultrabook documentation
The Framework Laptop Chromebook Edition puts a Google spin on the company's signature repairable, modular design. The result? One of the most capable, customizable ChromeOS notebooks you can buy.
MrChromebox.tech : Custom coreboot firmware and firmware utilities for your Chromebook/Chromebox
To install full EFI on a Toshiba, a "jumper" screw has to be removed to disable write-protect.
https://www.reddit.com/r/chromeos/comments/2ljid3/how_to_disable_writeprotect_on_toshiba_chromebook/
https://www.youtube.com/watch?v=JcZ711cxKdA
This guide provides step-by-step instructions for dual booting GalliumOS and Chrome OS on your Toshiba Chromebook 2 device.
