Trying to install R 4.0.3 on Debian 10 (buster) on a Lenovo Chromebook

I have a new Lenovo Chromebook which comes with a Debian 10 (buster) app. It's an app that runs linux in a terminal. I am trying to install the newest version of the statistical software R (4.0.3) but it keeps reverting to version 3.5.2. I get the following errors and no matter how many times I uninstall and reinstall r-base and r-base-core, it won't let me install 4.X.X. I've tried this fix: https://www.charlesbordet.com/en/how...0-0-on-debian/ but I still get the errors below. Any advice would be most appreciated!

The following packages have unmet dependencies:
r-base : Depends: r-base-core (>= 4.0.3-1~bustercran.0) but it is not going to be installed
Depends: r-recommended (= 4.0.3-1~bustercran.0) but it is not going to be installed
Recommends: r-base-html but it is not going to be installed
E: Unable to correct problems, you have held broken packages.