OK! I have got my Raspberry Pi 4 working with FreedomBox! Sort of…
Right now, when I try to install a program from the plinth UI it says something about backports not being signed or something. That issue is for another thread and another day 
. For right now, I have an UNOFFICIAL GUIDE I can share to y’all that can get you to a user account in your FreedomBox.
My hardware, Raspberry pi 4 2gb, 128gb microSD card, official RBPi 4 USB C power supply.
Prerequisites
I connected my RBPi to the internet using the wired ethernet cable.
I have not bothered to buy a micro HDMI adapter, this setup is headless.
Steps
-Download or torrent the Raspbian Buster Lite image file at https://www.raspberrypi.org/downloads/raspbian/
-Flash the image to a freshly formatted MicroSD card (above 8gb using Etcher or a flashing alternative)
-When flashing has commenced, make a new .TXT file in the “boot” partition named “ssh”.
(The text file contains nothing, it’s just the name that we changed to “ssh”)
-Safely eject the MicroSD card from your computer and install it into the powered off RBPi 4
-Plug the RBPi 4 up to a power supply
(The pi may or may not run on 5V 1A, the power specifications have changed from last generation.)
-Using one of multiple methods, get the ip of the RBPi 4 on your network.
(One method includes using the app Fing on the App store or Play store to scan your network. The device should be named raspberrypi)
-SSH to the RBPi 4 using the ip
(A program you can use is called PuTTY.)
If the previous steps where done correctly, you will be asked for a username.
-The default username and password for Raspbian on the image is “pi” and “raspberry” respectively. Enter those in.
-IN THE TERMINAL WINDOW, (enter without quotation marks)
“sudo raspi-config”
(an old school like UI will appear)
-Using the arrow keys, go down to “advanced options” and press enter
-Press enter on “expand file system”
-Press escape to go to “Finish”
-You will be asked to reboot, select yes
(Close your PuTTY window, reopen it 30-40 seconds later or when the raspberry pi fully reboots)
-Start a new PuTTY window with the ip.
-IN THE TERMINAL WINDOW, (enter without quotation marks)
“sudo apt-get update”
(Wait until it finishes)
“sudo apt-get upgrade”
-You will be asked if you want to continue, enter “y”
(Wait until it finishes)
“sudo DEBIAN_FRONTEND=noninteractive apt-get install freedombox-setup”
-You will be asked if you want to continue, enter “y”
(Wait until it finishes)
“cd …”
“cd …”
“cd var/lib/plinth”
“sudo cat firstboot-wizard-secret”
(You will see a short string of random characters)
-Copy the string to a piece of paper
-Close the PuTTY window
-Open your Internet browser
-Enter your RBPi 4 ip into your browsers address bar
(Your browser could say this is un-safe, this is on my home network so I didn’t worry much about the consequences of not having the correct certificates set up, click more options and continue to site.)
-When the FreedomBox asks for your secret, enter what you wrote down.
-continue the setup. You are done!
Unfortunately, the first thing I did was dive right in with setting up a Syncthing node. This didn’t work because that backports thing mentioned above. I’ll have more time another day to find the solution for that. I am new to Raspbian and Linux, my guide works for me so that’s good enough 
.