How to free up space for GTA 6

1. Go to Settings > Storage to see what is using space.
2. Open Console Storage > Games and Apps, choose the biggest games, and select Delete.
3. Worried about saves? Sony lists saved data separately from game data. PlayStation Plus members can upload it under Settings > Saved Data and Game/App Settings, and Sony also offers a full console backup to a USB drive.
4. Would rather not download a game again? Move it to USB extended storage instead (see below).

From Sony's storage support pages. Official

1. Press the Xbox button, then go to My games & apps > See all > Manage > Free up space. It suggests what to remove.
2. Or go to Profile & system > Settings > System > Storage devices, select a drive, and uninstall from View contents.
3. Microsoft says saves sync online when you are signed in, and removing a game keeps your licence and progress.
4. Under Settings > System > Storage you can also clear local saved games and Xbox 360 storage. Both stay in the cloud.

From Xbox support. Official

Both consoles can store current-generation games on a USB drive so you do not have to download them again. You copy them back to play. This is a cheap way to clear internal space, but GTA VI itself cannot be played from USB. See which drives work.