Was looking at the manual to see how the regen settings work. All I could find was the paddles setting -/+, but these are only temporary until you take the car out of D. My Kona EV worked the same way with the paddles. But you could also set 3 regen settings for each drive mode. That was permanent until you changed the setting again. I mostly drove in ECO mode and had it set for level 3 which is the strongest regen level, That made for very responsive and nimble one pedal driving. Worked great. Only time you touched the brake pedal was when you came to a complete stop and didn't want it to creep forward. It also had a Hold on Stop option, but I never used that. I liked the security feeling of having my foot on the brake pedal when stopped.
It appears there are no settings by drive mode with the Solterra. So the paddles have to be set each time you go driving. However, there is an S Pedal mode which is supposed to have a stronger regen level, but no settings as to how strong you want it. So will have to see on the test ride how this works.
I hate to be touting Hyundai here, but in general, and reading the Solterra manual, Hyundai seems to be way more advanced and sophisticated than the Solterra with the driver assist features. I found that also when comparing my Kona to my son's Tesla M3. It was pretty basic, and not a lot of settings for exactly how you want regen to work, and same with the autopilot cruise control. The Tesla was particularly bad in stop and go freeway traffic (basically useless), as it wouldn't brake until the last second (making you very nervous) and then lag on take-off letting people cut you off. Even my Crosstrek worked better than that. The Hyundai had a bunch of settings for how aggressive or mild you wanted to be, not just distance to car in front. Worked very well in freeway traffic, and you felt safe and confident with it.