I do not regret buying a step-thru. I am 62 and felt that at some time in the future I may not be able to swing my leg over the seat. Also, I plan on getting a cargo "thing" of some sort which may further inhibit swinging of the leg over the seat. One thing to check is the step-thru or stand-over height. I tried one that was 23". It was actually easier in my case to swing my leg over the seat than to lift my leg high enough to step through.
A quick check is this: The average kitchen chair seat is about 18" - 20". Put a broom handle across two chairs and try stepping over it. If it is too difficult to do, then you will not want a step-thru height in that range.
Regarding a rack: E-bikes are heavy and need to be supported underneath. I have this rack:
https://hyperax.co/products/volt2. I will need to get crossbars like these to put between the seat post and handlebar stem.
https://hyperax.co/products/ebadp. You will find many less expensive versions on eBay or Amazon.
I haven't tried the rack and crossbars yet, but when I do, I will drive around in my bumpy backyard a couple of times to make sure the bikes stay firmly secured in the rack.