Mondeo is the best choice for long, wide, flat boot and front wheel/saddle off, upright bike carraige. IMO, obvs.
We’re on our 2nd. We bought the first for precisely the same reasons – space, bikes, sleeping in as an option. We regularly get the bikes in the back and that’s how we do it. 120mm forks on a 29er no problem. 2 fit in on the small split, 3 or 4 on the large split (if 4, then a minute with the pedal spanner is worth it to save jiggling aggro)
When the 1st one died at 180,000 miles, we went to CarGiant and looked at all the big estates going, and bought another Mondeo. Lots are smaller and those that are comparable don’t make use of the space as well as the Mondeo – floor that’s not flat (octavia), sloping roof/tailgate (audis), narrow between the arches (passat, honda).
Looked at the SMax, but I think the load length with seats folded/out is shorter. Also, the tyres are expensive and some of the versatility comes from removing, rather than folding the seats. Drive to France with 3 and bikes in the Mondeo, you can un-pack, unfold the seats and take 5 on a trip to town. trickier in the Smacks.