Hi! As someone moving from 20 years of application development towards embedded software development, let me share my thoughts.
First, examine your reasons not to move into management or architecture roles and make sure they are valid, and not knee jerks. This is a whole big discussion in its own right.
Second, within your current organization, look for mentoring opportunities as a mentor or a mentee. Either way, you may find your knowledge and skillset expanded in an unexpected way.
Also, are there ways you can move horizontally within your organization? Maybe there's a tooling team, or a testing team.
Finally, just understand your own goals. Do you want to maximize income or savings over time? Do you want to maximize something else (fun? knowledge? recognition?) while reaching a minimum income or savings amount? Then, over time, reevaluate those goals and make sensible plans to reach them. Expecting excitement from doing the same kind of thing over a 40 year career is probably not a fair expectation.