Tell me, do you think it’s realistic to develop some kind of winning system or strategy in slots?

For example, bet small, and when a bonus or a series of successful spins starts, raise the bet. Does anyone have a positive experience?

Forget about strategies, it's all bullshit. Slots have a casino advantage at a distance, so any system will be negative. The only chance to be in the black is to catch the drifts and stop in time. That's it, no strategies.

Don’t listen to anyone, I raise quite well according to this scheme: I bet 10 cents on 1 line, if there are 10 spins in a row without a bonus and large wins, I raise the bet to 30 cents. If there are again 10 spins without bonuses, I bet.