You generally need not do coding as PM.... but, you should be able to understand how tech works...
like - there is a onboarding form to get user details. we need to understand what happens once a user submits the form.
Few things that happen are -
an entry will be created in database with the given user details,
an email will be sent confirmed that user is onboarded,
a SMS will be sent to the user
here, we should understand how the email and SMS be sent, are we sending or is there any third party tool we are using to send....
some tech skills we should have is
accessing database - where we can write read queries and get relevant data. this can help to analyze data ourselves without depending much on developers.... again, this is not too difficult, basic database knowledge is required and working little with developers to understand is enough
APIs - now-a-days, most companies are working in microservice based architecture and APIs play a very important role in that. So, understanding that would be helpful
basic things like what are cloud services like Azure, AWS etc., what is DevOps, what does QA team do, what is performance testing etc.