iPadOS 15.2 fixed the confusion over text selection. Double-tap and drag now works properly, and the stutter/magnifier bug is gone, making it much easier to place the insertion point.
15.2 did not fix the wifi problem. My iPad still sometimes loses its wifi connection while asleep, and the network must be manually reselected in Settings upon waking, instead of reconnecting automatically.
The most recent updates, released by Apple today:
iOS, iPadOS, tvOS 15.3
watchOS 8.4
macOS Monterey 12.2
macOS Big Sur 11.6.3
Security Update 2022-001 Catalina
Apple released the following updates today:
iOS and iPadOS 15.6
watchOS 8.7
macOS Monterey 12.5
Security Update 2022-005 Catalina
macOS Bis Sur 11.6.8
tvOS 15.6
HomePod 15.6