Qwerty just try it again.
It is fine, it's an upgrade to Android 13 from Android 12.1 It takes longer because it has to recompile your apps post-boot instead of during 'Finalizing'.
You've probably seen how long the Finalizing step usually takes, that is mostly moved to post-boot for this update due to 12.1 -> 13.
Android 13 is currently being pushed out via our Stable channel from our 8 update servers. Each update server has 2Gbit bandwidth and they've peaked at around 800 users downloading the update concurrently from each one. It's a large download and will go much slower than usual.
We use CAKE with a bandwidth cap for traffic shaping along with 128k tcp_notsent_lowat on our servers in order to fairly split the available bandwidth between each IP and also evenly between multiple connections from each IP. Can read about this here: https://grapheneos.org/articles/server-traffic-shaping
We could add more servers and we could divide up the GeoDNS regions more than we already have but the overall issue is cost. Our servers are already overkill for most of the year due to delta updates reducing the necessary bandwidth by 95% but that doesn't apply to major updates.