iMac in macOS recovery but don’t have a wireless keyboard connected

Heya guys! I have just bought a second hand IMac and the guy has done a complete wipe, which is fine but I’ve tried a wired keyboard to start it up and put it into Mac OS recovery but as it’s not a Mac keyboard it doesn’t seem to be booting the utilities menu up by pressing command ‘r’. The only alternative I have is a Mac wireless keyboard(oldish one) which I can’t connect with out Bluetooth function. Any ideas on how I can solve this without buying a new Mac keyboard? Or any other solutions as to why the wired keyboard might not be working? Thanks in advance!