Most website content management systems would never get close to that size. If you need a bigger database, D1 is probably the wrong solution to begin with. 10GB can be millions of records depending on your table structure. But if you are gathering some survey data, running a CMS, etc. you probably should be fine with even just a few MB of data; which is probably the sweet spot for D1.
Per their own docs, D1 is primarily meant for things like Auth DBs that you have frequent read/write access to but that store limited amounts of data.
If you need more storage, running Postgres somewhere else and querying via Hyperdrive is probably what you want to do instead.