It depends, on what you want to do. - Electronics is now huge, and have few extremely different parts, which could be all in one project. As example, you mentioned 3d printers, they have digital part, power electronic part and some could have optic (vision) part. To be honest, in University typical person learn few years, and become master in one part, and learn others by books or now by videos. What I see from my ex…
Chemistry? I barely studied that at all.
You needn’t be an expert but you should be able to read the chemical terms and data in a data sheet and not make a dangerous or sufficiently risky choice on component selection
This is especially important for hardware applications in adverse environments
For example, knowing that you need to use a tinned copper alloy if your device is going to be used in marine environments rather than pure copper due to it reacting to chlorides dissolved in sea water
Or realising that you would generally avoid using batteries as the energy source for mission critical activities in polar areas as the chemical reactions for SLA or Lithium batteries are dramatically inhibited at sufficiently low temperatures
These aren’t hard intuitions to grasp and follow when designing a system, but you can find your design can go catastrophically wrong even a few units outside every component’s operating temperature or overall environment
Graphs and performance on datasheets are generally linear but the consequences of erring too close to the metaphorical sun may be anything but linear!