Can you recommend another comprehensive design system? As an engineer, that's the most valuable thing about MD3: the figma design kit and per component design guidelines. It lets me offload a ton of workload I'd otherwise have to do myself (poorly) or outsource to a designer.
I haven't seen another design system that is as comprehensive to material. Express seems like an evolutionary refresh with some things I could use right away, but otherwise most of the content is MD3. It's valuable to me as part of the larger ecosystem.
I am not aware of a better alternative. It is a good question, that would be quite helpful!
What I did in the past (with M3) is to add some additional design tweaks (in flutter), like giving buttons an elevation. That worked when I had the designer on my side and since the app came from flutters M2 style, which had similar aspects. But it is cumbersome to argue against a google guideline with only usability knowledge and test results, and it also frankly depends on each component what can be done, which means the adapted design can easily become inconsistent if one is not careful.