There’s another free OSM based app that does have some traffic data, it’s called Magic Earth. Not open source though, as their business model is to sell adapted versions.

What does the size of the country have to do with it? Which good big and bad small countries are you talking about?

I think EveryDoor requires some relatively deep understanding of OSM before actually being a useful tool. So edits like this should be rare with that tool. Many of the edits like this are from when MapsMe was very popular and suddenly introduced editing, without enough nuance in the process. Bad edits do happen everywhere, you need a good balance between people who data curation and newbies making beginner mistakes. In some places, there’s a lack of experienced people maintaining the data.

In some places there are government basemaps available as well. These can be extremely accurate, up to centimeter precision. Of course they can be outdated or have mistakes too, and not all are as precise. So it’s hard to answer the question without knowing the location. Always vest to consult with local mappers about things like this.