There's some chances to get an idea based on the interview. People who care about code quality will try to ask you questions around the same. If they ask you around how to structure the code for an interview questions in a maintainable question, or how you would write a unit-test for something - that's a plus because it also shows they care.
Pure leetcode like algorithm questions are unfortunately very bad to judge that (in the same way that they are imho bad to judge the knowledge of the interviewed person).
If you are interested about test coverage and practices, looking at the domain of the company might help. Some have to comply with regulations (medical, automatotive, etc) and do more on enforcing to get this right. Obviously code coverage != good code, so the latter might still be on the worse end.
You can also ask in interviews what their test coverage is, and how they feel about unit-tests vs integration-tests. If they have answer things will already be much better than if they have none.
I think 3) works to some extent, and I think there is a small correlation between tech stacks, code quality and code coverage. Most C code that I've seen is very low on test coverage - and I guess that is because a mix of "testing C code is hard" (no nice interfaces/traits, no nice test frameworks) and engineers writing that code having more of a hardware than software background. But despite generally low coverage, there's still a mixture of C code which has better or worse structure. Code in new languages where a lot of users come from a more academic background and are programming geeks (Rust, Scala, F#, etc) seems more likely to have high code quality - but can sometimes also be overengineered. With the more boring managed languages (Java, C#) I usually found things are somewhere in between.
Lastly I want to recommend on simply not expecting too much - things are usually very mixed. More important than the current state of things is also how much you would be empowered to influence and change the status quo. Teams where things might be lacking, but where all contributions to make it better are valued, can still be good.