I've been doing this stuff for about 15 years now. Longer than many, not as long as some.

In my opinion, good architecture should be easy to extend, easy to scale (up and down), easy to reproduce. Microservice architectures are easy to scale, but usually hard to reproduce (any amount of config per service adds up a lot) and can be very hard to extend too (any changes to one service might ripple to many others, with knock-on effects)

One of my biggest red flags for a bad architecture is if you cannot easily create a (preferably localhost) development environment for it. I think this is where a lot of microservice based projects stumble. It leads to a lot of brittleness and a very siloed development team in my experience. Replacing what should be a library call or DB query with a network request to another service (which then has to query the DB for you) is a certain kind of lunacy.

Frameworks that are very opinionated are also very bad in my opinion. Depending how strict they are if you're doing anything even remotely unexpected you will butt up against the limitations of the framework often. That's annoying to me, I prefer to build my own stuff.