It’s also worth understanding that even the most precise, non-simplified border data isn’t going to be perfectly correct at the level of tens of meters. In fact, a large proportion of the world’s borders haven’t even been defined that precisely, or in some cases even to the level of kilometers. And where borders were defined precisely, but before the GPS era, their exact correct course often depends on the actual locations on the ground of a series of decaying boundary marker stones whose precise coordinates may not even be recorded anywhere at modern levels of precision. (Luxembourg and Belgium are almost certainly exceptions to this though - most borders in Europe have long since been defined at high precision.)
If anyone is interested in this topic, precisely defining borders is called delination and marking their definitive locations on the ground is called demarcation. If you search for news about it, you’ll see that the process is very much still ongoing in many countries.