I would certainly suggest to take an actual look at the cars themselves.
If boot space is something you need, Sedan it is. In terms of rear seats, I don't think the space is that much different, but due to the door design, Liftback windows are smaller, but you really need to sit in the actual car to determine if its okay for you. Just looking at pictures won't cut it.
From the previous posts and what I know,
Bermaz Jalan Ampang has a Sedan H+ (pre-2022) for test drive
Mazda TTDI has a 2.0 Liftback show car (2022 model)
Mazda Cheras has a 2.0 Liftback test drive car (2022 model)
I would recommend getting the H+ because of all the additional safety features, especially
Blind Spot Monitoring, Rear Cross Traffic Alert, Smart Brake Support
I wonder how long would you need to wait if you book now
Exactly my sentiments. But most cars require waiting time of at least 3 months now.