What should we do about the fact that Modern Hebrew has almost no connections to Biblical Hebrew? Is this a sin? Is it still a Holy Language? Why or why not?

ב"ה Shalom I don't understand, what made you reach that conclusion. I would say, on the one hand, that modern Hebrew is based very much on Biblical Hebrew and not just by the use of words but also grammatically. On the other hand, though I am not a linguist, Hebrew, has never been a static language. The language of the Mishna, is not the same Hebrew as the Bible either. We can see in the Mishna and Talmud a clear infiltration of Greek words. In our times, we see the same. So , the basis of the language is definitely holy since it is the language used in the Torah. However, as far as speaking Hebrew while in the shower, for example, it is the content of what is said which matters or if the word refers to G-d, such as "Shalom" which would be forbidden to say in the bathroom. The same applies to bringing in Hebrew into the bathroom. It is the content which matters. All the Best Gmar Chatima tova