You can if you have the right phone, namely pixels. Ironic because its the Google phone, but the Pixel line has the most custom firmware development.
LineageOS for a more stock version of a de-googled ROM. Works on a number of Android devices. GrapheneOS for a completely de-googled firmware that is tailored for privacy. Snowden said if he were to use a phone it'd be a Pixel running Graphene. Only works with Pixel.
raoulvolfoni