Well... My experience with maps download is as follows, and I think all comes down to the device's age and/or hardware...
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4-year old cheap Android phone: Impossible to download maps
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iPhone SE 1st Generation: Downloads maps but takes its time, not that fast but not slow.
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iPad Pro 2019 12.9inch... fastest of all three devices, by a long shot.
So... The new app seems much more suitable to more powerful phones and tablets.