That grocer likely has loans which are now much more expensive in real terms. Same with the farmer who sells their goods to the grocer. The manufacturer of parts to repair cars also has them. With deflation, all of them bring in less money but have increased real costs. So they cut costs by paying workers less or more likely laying them off. It's good for banks though. They have loans out that now get amazing returns and can simply stop loaning money out because just having the money sit their provides a pretty good return.

I’m not even sure what you’re taking about it. But from the worker/anti capitalist perspective, deflation is even worse. The working class, who holds huge amounts of debt like student loans, ends up paying more as the value of money decreases. Imagine all of your student debts increasing in real value over time, on top of the already existing interest rate.