Should I return my S size Speedmax and get an XS?

So recently Ive gotten the speedmax in S despite canyon recommending me a size XS (inseam 78cm) i took a look at the geometry like the seat height and reach and I think I can make it work. However i had totally forgotten to see the stand-over height which is taller than my inseam height. I can ride the bike and the fit feels comfortable, but when I think of getting on/off the bike I feel a bit erghh why is this bike too tall?

But the XS comes with 650b wheels which means a hassle to find the tyres and I need to bring my own spares on group rides. Can anyone give me any input on this predicament? Should I return to get the correct size or just wing it with a size S?

Attached is a picture because well why not