Finding HU games becomes a huge problem when you move up to low/midstakes and beyond. I have given up on playing heads-up tables. I can open 20 tables with one player sitting and I will end up with zero games a minute later because they look me up on ptr, or they see how many tables I'm playing, or they know my SN. That's a real problem for the heads-up games. You have a thousand terrible regs who do nothing but bumhunt.
Obviously you're free to do everything within the rules to maximize the profit. But I'm positive that poker sites will think of a way to combat that much like they did with the professional shortstackers.

The win rate will not really slow down otherwise. The players down here are so bad its funny.
Who would have thought that people are bad at microstakes!
No, the winrate will slow down. idk how many hands you play... but 1k in 6 weeks of 5NL means you're running hot for sure. Even with a 10ptbb overall winrate you could be breaking even or slightly loosing over the same sample just by running into the other end of variance... but you'll see for yourself soon enough.