>I would like to transition to complete plastic frames in order to save hours upon hours of work building frames and inserting foundation.
Then go Foundationless, save a dollar a frame plus the time.
Bees don't like plastic they will only draw them on a strong flow, and even then they can cross comb them up trying not to build on them.
>Are there any brands out there that don't have these indentations?
Not that I've seen.
>Is there a reason why every complete plastic frame has these indentations?
to save money for the manufacture.
Plastic is a necessary evil if you want to regress your bees to small/natural cell. You can do in one step with PF 100s from Mann Lake.
If you are going to use plastic frames add more wax to the frames there is nowhere near enough wax on them. Use a roller, the thicker the wax the quicker the bees will accept them (don’t use so much you fill in the cells). Even then it will not come close to how quick they will work a foundationless frame.
I've noticed there does not seen to be more beetles in a hive with all plastic. The hiding places in plastic frames are the same as empty cells in comb. A strong hive will keep the beetles at bay. Shaded hives have more beetles. Some place have beetle a lot worse than here.