How to start research in a field with high standards? I'd like to do research on the field Natural Language Processing. However, the current state-of-the-art (BERT) has raised the standards and for me it feels discouraging to start in this field. Should I avoid doing research NLP since it will cost me a lot of time and there is a risk of not improving upon the current standard? Or should I focus my research on the limitations of the current state-of-the-art? Or should I broaden the topic and focus on a different related topic? What would you advice in this situation?

And besides that, do you start with an research question or would you do an initial literature search first?

Best,
CamelCase
For simplicity sake assume that there is a dichotomy of research topics: those where a lot of active research happens and those where that is not the case. 

In areas where a lot of research is happening most (all) the "low hanging fruits" will have been taken and you will have a hard time making really big contributions. On the other hand there is an active comunity of researchers that cares about this topic, and also cares about your (smaller) contributions. 

In areas where not a lot of research happens, you are more likely to find low hanging fruits, and you are more likely to make big contributions. However, there is a reason why not a lot of research is happening in that area: few people care about what is going on. 

Real research areas are much more complex than this, e.g. some areas where not a lot of research is happening now were very active in the past, and there is not a lot of low hanging fruits left. Moreover, it is not so much a dichotomy but a gradient. But you get the idea of the trade-off between making small contributions that many researchers care about (and are thus easier to get published) and making big contributions that fewer researchers care about. You can also see that both are viable strategies.