How to compensate for shoes too big

Hello everyone,

I bought shoes (Yonex Aerus Z) that are half a size bigger than my usual size (EU44.5 while my usual size is EU44). During the tryout in the shop it felt ok, but now on court it feels way too uncomfortable, like I could fall at any moment from my feet slipping in the shoes.
Does anyone have any trick or advice on how I could make the shoes fit better? I see a lot of threads about insoles here, would those help?

Thanks in advance!