I second the Honda Jazz, I have a 2010 MK2 and I can comfortably fit (rear seats folded) an Orbea Rallon, size M, rear wheel first front wheel off and secure it upright with 2 straps on each handgrip hooked to the boot hooks and 1 bungee over the top tube, no need for extra stuff.
Been doing this for years and never a single issue, including multiple 2000 km roundtrips.
I’ve also occasionally carried 2 bikes upright, the Orbea and a custom hardtail which is a bit longer, and while not particularly easy
This is with the a mk2 Jazz, the mk3 inside space is basically the same, unfortunately the current mk4 has less interior space due to the batteries, so this should be confirmed with a practical test or by taking measurements and comparing the 2.