a project table in Notion tracking everything they are working on in life

a Car Maintenance database somewhere to track most things you do with the car. E.g. registration, insurance, finance etc. that's neatly maintained and kept up to date.

"Get tires for car" is a project you're currently acting on. So it goes under current projects.

Car Maintenance Database is a bunch of car history you've decided is valuable to you; it's useful info but not currently being used by any project. So it's in the References folder.

Once the project "Get tires for car" is complete, the information that is valuable gets saved under the "Car Maintenance Database", in the References folder.