"The problem of xxx continues to attract great attention of researchers." "continues to attract great attention"... This part of the sentence is fine. In fact, you will see it in a lot of scientific papers. "of researchers"... is not correct. You could say "from researchers". So one way to fix your sentence is this... "The problem of xxx continues to attract great attention from researchers." But an even nicer way is to write it like this... "The problem of xxx continues to attract considerable and increasing attention from researchers." (leave out the "and increasing" part if this is not true).

Another way to say it is: The problem of xxx continues to be a subject of great interest to researchers. I personally find this version slightly smoother reading than your original, but it's just a subjective preference. Another thing you can do to improve it is making "researchers" more specific, like "behavioral science researchers" for example.

The problem of xxx continues to attract the attention of researchers. The problem of xxx continues to be a great attraction to researchers.

Good job! That sentence does sound very natural. It is a good introductory sentence and I hope you get a good mark on your paper!

is that it continues to attract more researchers.