Cordless vacuum cleaner ?

No, can hold it down OK, but hate cleaning it out. Make more mess about half the time. Perhaps yours in faulty?

Yes! Why can’t it have an on/off button

My Gtech cordless has an on/off button.

The new GTECH hand held one has an on/off button I think they must have realised it was a design flaw not to have one.

After using mine (another brand!) yesterday , my thumb is so painful I can hardly use it. It’s true I injured it over twenty years ago but until now has never given me any trouble. I’ve had the machine a couple of years but shall now be looking at the G tech

I've got a Dyson stick vacuum. I use my index finger to hold down the power button. It's like having your finger on the trigger.😀
I don't have many trouble with it at all.

Mine has a trigger too.

Mine has a trigger grip too so I use my index finger without any issues.

We are seriously thinking of getting a Dyson very soon, but I haven’t actually tried one yet so didn’t know about the trigger issue. Not sure I like that idea, but DH will not countenance looking at other models.