I don't mind if it cannot connect to a big screen as I have built a kind of laptop at home from my smartphone. What I done was I took out everything from a laptop shell but kept the screen. Purchased a controller (vga + hdmi) to the screen, a usb vga adapter for screen mirroring and a usb hub for the keyboard and mouse. Then I squeezed everything into the laptop shell including a wireless charging (only the thin coil without its house) + a keyboard from an old 10" tablet.
Then I can plug the screen into the main (or a battery pack with 12V / 3Amp output), connect the usb hub to the phone (S7) and slide the phone into the shell onto the wireless charger. And voila, my phone is my laptop and my laptop is my phone. I don't need big screen or whatsoever.
I even got the MS Visual Studio Code installed and ran on the full ubuntu 18.04.
I have done this about two years ago but the concept still works, but collecting dust on the shelf.
The only downside was: on my S7 I could only run Linux on top of Android in a chroot (with the Linux Deploy app) and there were a few limitation:

• no 3d acceleration as I had to connect to the chroot with VNC
• I could not make cups working with my network printer (probably this was kernel related as I got it working on my Galaxy S2 with a similar setup, but the S2 was much slower and it had other limitations)
• on newer Android roms I lost sudo (root only worked if I sshd into the chroot as root)

So finally I abandoned the project and started looking for something native. Then I found UT why I purchased my Nexus 5. Then because I didn't like UT I ended up with Sailfish and I love it. Unfortunately PM doesn't install anymore in multirom, so cannot try. (I have tried it on my Galaxy S2, but that is far from the one for the Nexus 5.)

It would be cool to use this custom laptop shell with the Nexus 5 but I think the main issue would be the slip port. (On the S7 I needed to install an Adroid app be able to mirror the screen to the usb vga adapter, but obviously this won't work on Sailfish.)