Firstly, thanks for everyone's replies!
From the replies I've got, I've learnt about int and ext cam skewers. Mine is of the latter sort, which after some reading isn't the best due to compression of the soft plastic material. Looks like I'll be changing them out with int cams. My bike is a Polygon Xtrada 5 2021, don't think it has a big following. In the way of maintenance, I've only fine-tuned gear indexing and cleaned the chains, haven't got to replacing grease on the cranks or wheel axles yet, but the qr problem already presented itself a month after purchase.
The cassette doesn't only wobble, it actually rotates in the direction of wheel travel when coasting and that is what i suspect is slowly loosening the tension on the skewer.
I'm unable to tighten the skewer in any other way than turning the lever because my bike stand is attached to the threaded end of the skewer in place of the nut. That makes it impossible to fine tune the tightness.
Perhaps it's also worth mentioning that after a short distance and when i put the stand down, it oftentimes buckles with an audible creak coming from the axle and that causes the rattling sounds caused by improperly seated wheel in the dropouts when spinning the wheel. Opening and closing the lever temporarily solves it until i ride it a distance again