This is more or less the suggested strategy at maniac tables where things are often capped preflop and on one or more streets.

In less aggressive games, not playing all those hands will cost you +EV, but reduce your variance. If you play poorly post-flop, then it's probably better not to play those hands, which might be where you're at at this point which is why the system is working so well for you.

Once you're comfortable, you should try adding hands back in.