Hi SirRonny, welcome to finally getting your first post up on the Forum! :clap: :congrats:
As for those 'splined lug nuts', they definitely
AREN'T BRP OEM kit, they sound very much like they are the a/mkt security lug nuts that you can buy to try and stop wheel theft, and as such, they'll need an appropriately splined 'key' type lug nut that goes over them to allow you to remove the nuts & key together with the normal tool. I'll see if I can get you a pic of one type...
Have you checked thru the bike & all it's storage for an odd looking thing that sorta looks like a 'lug nut extender'?? If you can't find it on/in the bike anywhere, you might try contacting the previous owner; failing that, most tire retailers who strip & fit new tires on your car while you wait usually have a fairly comprehensive set of these 'keys' to allow them to get the wheels off when the owner/driver has no idea where the key is!
OR, you might need to see if anyone can identify that particular lug nut spline so that you can buy a replacement key... And if all else fails, it generally takes about 10-15 minutes carefully using a blunt ended drift to manually hammer/drive each of the splined lug nuts off!
Hopefully, your key is stashed on/in the bike somewhere, in the glovebox, maybe even in the tool kit, or possibly in the placcy envelope the glove-box manual is usually stashed in? :dontknow:
Ps: The pic below is of a well-used, long-reach, narrow walled key, with the splines on the inside end away from the hex (well worn - bloody lazy tire techs using rattle guns again!

) that are designed to fit over matching splined lug nut on an alloy wheel with deep holes and little room to squeeze anything in around/over the lug nuts; there are many that are smaller, shorter, &/or fatter, but they just have a normal lug nut type hex on one end, and a fatter other end where it slots over those splines. :thumbup: