Strictly speaking, no. No one customizes anything. They say they want that, but this is a flaw in listening to users. If you watch their behavior, no one (I mean, 1/10th of 1%, at best) customizes.

Now, that isn't to say mapping is good, readable, or often applicable to contexts. Aside from increasing contrast across the board, I can easily imagine contextual changes to maps to make them work better. Let's assume mobile usage now, as that's the key for mapping. When driving, for example (and let's admit people look at their phones to navigate), the map you use sitting at your desk could:
- Get higher contrast
- Get larger labels
- Only label items you need, such as roads you are on, or which intersect the route, not others
- More clearly indicate your position, and the route

It could also do things like automatically turn on traffic status, and turn it off again when sitting and walking around. The user can over-ride these settings, but we know enough about user behaviors in various contexts, and can pretty well sense their context from sensors on the phone that we should give them a better experience, automatically.

I've done a fair number of mapping products, including some user research into this, so would be happy to discuss it further if you have additional questions.

It depends what you are trying to achieve. I would need to know more specifically what you are trying to accomplish in order to give a better opinion or recommendation. There are many great map solutions out there and if you can find one that works, you are saving a lot of backend work.

No. You may want to rephrase your question with an open end question to be specific about what you are asking.
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