Eh, on my Latitude(5290) - 2018, i7-8350u and my shitty home network (still better than my grandma's ADSL but not by much), zypper dup (with some unnecesarry shit) takes an hour. I assume emerging the upgrade would be at least 10 times longer.
I assume I'd be forced to use Gentoo if I eventually switch to a snapdragon laptop, so fuck me then.