The “fidelity of your prototypes” should evolve over time. I highly recommend starting your prototyping journey with various low-fidelity prototypes. This allows you to quickly explore lots of different possibilities early on and continuously learn about the problem space and the solution space of your ideas. Low-fidelity prototypes can be built much faster and with simpler means. For a low-fidelity prototype, think of your time investment in terms of “a few hours” versus “a few days or even months” for a high-fidelity prototype. In general, only, advance to higher-fidelity prototypes once you have learned enough about your most critical assumptions “quickly and cheaply”. You might also consider building mixed-fidelity prototypes in which you merge high-fidelity and low-fidelity elements of your product in a single prototype.
Remember, your goal with prototyping is to learn. Avoid the pitfall of building a prototype just for the sake of having a prototype. You can direct your prototyping and learning efforts by formulating research questions or hypotheses beforehand. If you set up a clear learning goal upfront, choosing the appropriate fidelity and method for your prototype will become much easier. Besides, the learnings you will gather will be easier to incorporate into your overall product development strategy.