If you can set up a harmony activity for it that you like, then you can start that activity through SmartThings.
This doesn’t always give you the level of granularity that you would need, though. But it does let you schedule an activity to start and end, which might be enough for the Hoover.
It’s all going to come down to whether you can put the instructions that you want in the “steps” of a harmony activity, or whether you’re trying to replicate some button pushes which are not in the activity itself.
When using harmony with SmartThings, it’s always done on the activity level, so the first thing you have to do is create a harmony activity that does exactly what you want. Then you can initiate that from SmartThings.
Just using a pocket socket (regardless of the protocol) may not help much. All that can give you is current on/off and these days many electrical devices won’t start operating just because power is restored.
So if you already have a harmony, I would look into those options first.