So I am on lichess in the 700es range and I continue to have these players as opponents who early on attack really aggressively.They must have some success with this (element of surprise I guess), but if I look at the stockfish analysis there moves arent so smart. (difficult enough for me to fend off though). I sometimes feel a little dumb, though because it can be quite hard to find out how to stop their attacks..
I guess it could be that your opponents are beginners too that don't know what they are doing. Or someone even trying to be super aggressive on purpose to throw newbies off balance. I like to study the theory of openings but sometimes even forget the sequences in actual games and make moves that end up being aggressive and stupid that analysis later shows the opponent had a major advantage.