Some games do let you manage their installs. Halo: The MCC for example. Lets you choose not to install each individual campaign or multiplayer component, so if you don't PVP you only need to install the campaigns, if you believe Halo 3's multiplayer is the one true way to experience pvp, you only need that installed, if you aren't fussed for the Master Chief, or prefer Firefight, you can only install Reach and ODST
One reason for some of the overly large installs is that PS5, unlike XBox, has a 64GB limit for DLC sizes. Any additional DLCs that go over that, the console cannot see. Dovetail Games have spent months working on a bespoke software workaround for this in Train Sim World as each route DLC for that game is around 5GB, so to install all of it on an XBox or PC takes around 200GB, meaning if they were to use the standard solution many devs do for this of bundling everything in a single install and having 10MB "unlocker" DLCs, players who only own 5GB worth of DLC would need to install an additional useless 195GB of content they cannot use