This is probably gonna crash and burn but I want to get the idea out of my my head.
Allow players to buy/rent a ,"Workshop/Makerspace" at stations. This could be any station they prefer to set as a home station, or their carrier.
Perhaps even have it as an optional module on the largest classes of ships, like we currently have with materials.
From this workshop they can apply blueprints to build parts, components , munitions etc.
Some of these rarer parts could be purchased/shipped from engineers or found naturally or found at biological, guardian, thargoid sites etc.
Blueprints for parts could be purchasable in many places , or in some cases found or purchased from engineer, but reusable once this is done, you shouldn't need to keep visiting the engineer.
A player if they wanted then could park their carrier above something like a guardian site and create derived components to seel from their carrier.
Someone far outside the bubble in an explorer Anaconda could reproduce new advanced components from stuff they find.
Stealing blueprints from a base might make more sense when you can use them yourself.
Source: https://www.reddit.com/r/EliteDangerous/comments/sq9iom/proposal_personal_workshop_an_engineers/