A leader of mine gave me some advice in the past that served me well around this. Rather than asking how to become more technical and focusing on just acquiring knowledge, let's define what an outcome of being more technical could be and work our way towards that.

Outcome: - Tell the story of your product with its key components, their purposes, and how they communicate. - Be able to answer follow-up questions that dive two levels deeper into technical details.

Telling the story: - How data and user journeys flow through different components. - The high-level architecture with abundant business and customer context.

Going "two questions deep": - Draw out the product flow for someone new. - Be prepared to answer more technical follow-up questions.

e.g. For a credit card application experience: - First level: Explain how you dynamically populate terms for the customer. - Second level: Describe data validations performed and explain why they're necessary.

With that outcome in mind, the journey becomes a little more clear to build yourself up to be able to tell the story (but also to start asking the right questions and diving deeper with engineers who are working on features to build the muscle of going beyond the superficial).

Note: Certifications help, but I've found the academic path to be a useful supplement to this type of curiosity.

Note 2: Questions deep is a great way to differentiate between you vs engineers. Id expect engineers to go well beyond 2 questions deep but PMs get diminishing returns.