Opponent outplayed me in the opening, but failed to capitalise.
French Defense or Sicilian Taimanov or E5?

I know this is sorta late, but good job! You might already know by now, but that opening is called the london system. It's a pretty solid line for white that generally involves the same move order. d4, Bf4, e3, Nf3, Nbd2, Bd3, maybe eventually going for c4 or e4. I think you played well in the opening up until when you decided to play Ne7, which was probably a bit questionable(The knight is better placed on f6 anyways, although I'm guessing your idea was Ne7-c6). On move 2 you could have played c5 anyways(if dxc5 then Nc6 followed by e5 or e6 is just good for black) and than Nc6, Nf6, and then Bf5 and e6 without having to block in your bishop on move 2 with e6, although that is a perfectly acceptable line. Good job anyways, though!

This is what always happens to me in matches - I prepare some lines and end up facing something quite different. To return to the French, one advantage of playing it is that club level opponents seem to play mostly one of two lines against it. If you want to save study time, you can prepare carefully against the advance and exchange variations, which you will probably face most of the time, and play dxe4 against both Nc3 and Nd2, leading to the solid Rubinstein or Fort Knox, which are easy to learn.
My opponent played a Queens pawn opening that I was completely unfamiliar with, bringing his bishop out on move 2. I won anyway, perhaps thanks to chess.com’s tactics practice room. Thanks for your input.