There has to be an overarching thesis that is well-formed (formed based on experience/tests from adjacent/related markets, key assumptions validated at reduced scale, strong backing by investors/founders etc).
During this vision formation/validation stage, keep things very lightweight and don't over-invest in prolonged tech platforms.
For example, if your product/service has an on-the-field operational part to it, then run that part with manual operations with pen/paper – pen/paper is extremely flexible and universally usable and survives all kinds of surprises in the field – don't wait to build a software solution to test your thesis in the field. Manual ops can scale quite well especially during learning phase (scale is not your goal, learning/validating is). Choose the use-case for your experiments carefully – optimizing for fast learning and applicability of that learning for next adjacent use-case you intend to expand to.
Once you get going, still build the tech systems without dogmas or baking strong opinions in too much. Keep your engineers generalists and first principles problem solvers and interested in solving both tech and functional-domain problems and encourage them to be humble and curious – because both the functional and tech world is constantly changing. Don't hire a huge product management org – every engineer/manager should be thinking about customer/product first. Over time, parts of your product are more mature and parts of your product are very nascent and still volatile. If your entire team is still thinking customer/product first and build tech to solve problems from first principles, then they should have found the right coupling/cohesion balance between different parts of the system to avoid shared fate, high blast radius or high contagion of that volatility/instability affecting more mature parts of the system.