You can't really take advantage of the undercut bots because they're able to set a price floor that they will not go under.

You can feel them out to figure out what their floor is and sell just below it, but the next time they check the bot, they'll just make the floor even lower and keep playing a game of "how low can you go" with their legit competition until they back off because the time/money ratio becomes too low to bother with.

These days, it feels like the only time you can make much profit via mainstream goods like consumables and crafted gear is within the first weeks of a major patch before the bots get updated and they start digging their feet in.