I would expect that for a fairly heavy person that a more powerful motor with a lot of torque is more important than it's speed rating.
For example, if you were considering something from Trek (which I researched a lot before buying), I would have recommended the 20mph 75NM Powerfly over the 28mph 63NM XM700+ speed pedelec, because the slower bike has more torque to get a heavier person moving, especially on hills. At 215 lbs I didn't have any trouble climbing with a 50NM Dual Sport+ at 200%, but the 75NM Powerfly makes steep hills almost effortless at 300% assist.
The Vado 5.0 seems to give you both high speed and 90NM torque, with a larger battery to support the extra power you might draw (350W vs 250W of the 3.0). Regardless, with the mid-drive taking advantage of the gearing I'd expect most of these bikes with over 50NM to work up to 250lbs (max rating for Trek), depending on the number of hills you have to pull.
With both offering 90NM torque, maybe your choice could be based on (1) big price difference and (2) whether you will be riding in places that only allow a class 1 eBike (eliminating the 5.0).
However, Court has the Vado 3.0 and 5.0 both listed as providing lower % levels of assist than Trek, at 20% ECO, 50% Sport, and 100% Turbo. I don't know if that is a typo, but I fear that you'd have to own extremely powerful legs to get the full 90NM out of the motor at only 100% assist. I've run into some hills that have required the 200% support level that the Trek eBikes offer, and some where I was stuck at 5-7 mph uphill if I chose to stick with only 100% support, but I am disabled with only one working lung and fibromyalgia.
I've tried the same steep hill with a 50NM Dual Sport+ and 75NM Powefly 7, and 100% was almost not enough in some parts of my climb, although it was doable at slower speeds. But the 120% assist of the Powerfly in Tour mode was a noticeable bump over the 100% of the Dual Sport+ in NORM mode - and that same hill with 200% pedal assist doesn't make me stop to rest and sees 10+ mph speeds (while my 300% feels like cheating).
I'll have to go watch Court's video reviews now.
EDIT - I mention the hills, even though your ride is flat, because hills make the bike perform as if I'm heavier than I am, which could replicate your experience with an extra 30 lbs to push.