some work might take me 1 hour and someone else 2 hours (or vice versa) and that would be reasonable

there isn't a set amount of time for a task to be complete - some are faster, some are slower. people work at different paces.

but if you can do it in 1, and take 2, and 1 hour of that is you going running or playing video games... then that's not the same thing at all

were I your employer, and I found out half your working time is spent doing personal stuff, I'd argue to pro rate your pay for the time you're actually working

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what's the problem here again?

you're not paid to do your own shit, if your employer knew that 50% of your working day was spent doing personal stuff, they'd give you more tasks