How I saved all my data after Tahoe bricked my computer

*see "Another Tahoe'd dope self flagellates for your amusement" for back story*

Requires 2 external hard drives. One about 20GB and one as big as all your data is going to be.

My laptop is a 2017 MacBook Air 13". It has an Intel chip

Steps

#1. Turn off computer. Plug in your external HD with about 20GB.

#2. Boot in Recovery Mode by pressing On as well as Option, Command and R. (This key will prompt the computer to offer you the last supported OS - in my case Monterey). When I just did Comm-R I was offered Sequoia (last installed OS) and had no internet connection. With Opt-Comm-R I had an internet connection.

#3. In the Recovery screen go into Disk Utility. In the 'View' menu select 'Show All Devices'.

#4. Select your external hard drive from the left. Select the topmost option in the stack. Click "Erase" then make sure the Format is APFS and the Scheme is GUID Partition Map. Erase the disk. (I also went from the bottom and did first aid on each section of everything first). Quit Disk Utility.

#5. In the Recovery Mode screen select "Install Monterey". Go through the prompts and INSTALL ONTO THE EXTERNAL HARD DRIVE. Once it has finished installing reboot the Mac using the external hard drive. (Turn on the computer and when prompted, select the external hard drive).

#6. In your new Monterey desktop, open a new Finder window. Select your Computer's hard drive on the left hand side (mine was called the default 'Macintosh HD'). From here you can view all the documents stored on your computer.

#7. Move any files you want onto your 2nd external hard drive. Then go back to Recovery Mode, Erase the HD with Tahoe on it and then install Monterey onto the HD.

#8. Download OCLP again ;)