I have some Milwaukee cordless tools: M18 hammer drill, angle grinder, hackzall, jigsaw, rotary tool and my go to M12 drill, which gets a hammering. Excellent tools which I've never had a problem with. I also have some cheaper Ozito cordless tools: Drill, saw, angle grinder, rotary tool, LED light, impact driver and a few others, batteries are the problem with them, but they can be reservice by taking them apart and recharging the cells individually.
Impact drivers are excellent for removing stuck screws and bolts, as long as they are used with good quality bits. I would be reluctant to use them for tightening small screws though, lest you strip the threads.
I also have cordless screwdrivers, Bosch and Ozito. The Bosch is grossly underpowered, but does come with some handy accessories: Right angle driver, offset driver and so on. Bosch tools are pretty hopeless tools through. The Ozito screwdriver gets a hammering though due to my inability to use manual screwdrivers.
Cheap cordless tools have their place, mostly for tools that require a lot of torque and tools that get used infrequently.
I have a cheap Chinese corded 4" angle grinder, that I've used and abused for over 20 years but it just refuses to die. Not all cheap tools are rubbish!