That was it exactly. Thank you.

This was a journey, so I'm documenting it here for anyone who might run into a similar situation.

I'm using a Chromebook with Linux enabled.

To confirm my version of Python I ran python --version:

Python 3.9.2

OK! Getting somewhere. So I have to check what distribution of Linux is installed with grep '^PRETTY_NAME' /etc/os-release

PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"

Alright. Google says if I want to upgrade Python on Debian 11 I have to compile it from source. Yikes! But, wait, there's a PPA - Yay! But the PPA is for Ubuntu - Boo.

There isn't an active community for ChromeOS on Lemmy yet, but that other website has directions for replacing Debian with Ubuntu.

I'm lazy so I'm not doing that. I'm just going to spin up a temporary Ubuntu container that I can delete later, so my directions are much simpler:

Ctr-Alt-T to enter crosh, the ChromeOS developer shell.

vmc start termina
lxc launch ubuntu:22.04 ubuntu
lxc exec ubuntu -- bash
apt update && apt -y upgrade
add-apt-repository ppa:deadsnakes/ppa
apt update
apt install -y python3.11 python3.11-venv
python3.11 -m ensurepip
git clone https://github.com/Ac5000/lemmy_account_sync.git
cd lemmy_account_sync/
pip3.11 install -r requirements.txt
cp exampleconfig.ini src/myconfig.ini
nano src/myconfig.ini
python3.11 src/lemmy_sync.py

Success! I had to escape some special characters in my passwords, but that's easily Google-able.

I'll be keeping the container around for a little while to do some periodic syncs. Then I'll remove it using crosh.

vmc start termina
lxc delete ubuntu --force