But it happens, for example, that someone can do parts of their tasks from HO and hand over the parts that have to be done on site to the colleagues who are already on site anyway.
From my point of view, that simply wouldn’t be okay without further changes. So either they are not allowed to just hand over the tasks, or if it still makes sense from a process perspective, then you can do it this way, but accordingly the warehouse workers must either be better paid or get reinforcement.
then they save time
Paid for 39 hours and then maybe only work 34 hours from HO
Well, it is not called the time-cost-quality triangle for nothing. Usually, the error rate will decrease first, or things that were left undone will be taken care of. If more tasks come in, more/faster work will be done; if not, something is actually wrong, but one would have to look at it individually. The problem is that such managers usually don’t look more closely but only look for arguments for their preconceived opinion.
then I'd rather have them sitting here instead of hanging their laundry at home, showering, or unloading the dishwasher
QED. Instead of thinking up new tasks, they should rather sit around dumbly. Sorry, but your boss-to-be is a bad manager.
a difficult topic, at least for us
More like a difficult boss, unfortunately not just for you.