As for the "Service Recommended" battery status condition I can say that this is a sad change Apple has made with macOS 10.15+. This battery status can mean macOS had detected a hardware failure with the battery or the battery capacity may have just dropped below a pre-determined point Apple has determined users will find battery life to be less than optimal. Here is what the "Service Recommended" battery condition means from this Apple article:
https://support.apple.com/guide/mac-help/check-the-condition-of-your-computers-battery-mh20865/mac
Service recommended: The battery is performing normally, but its ability to hold a charge is less than when it was new. You may want to consider replacing the battery.
Note: The battery may also not be functioning normally, and you may or may not notice a change in its behavior or the amount of charge it holds. Take your computer in for service. You can continue to use your battery before it’s checked without harming your computer.
Before macOS 10.15 Apple actually had a much better and much more informative status indicator which was separated into four conditions instead of just two now. Previously macOS provided status conditions of "Normal", "Service Battery", "Replace Soon", and "Replace Now" which meant the battery was good, macOS detected a hardware fault with the battery, the battery capacity had dropped below 80% of the original design capacity, and the battery capacity has dropped so significantly that you will probably only get one or two hours of runtime on the battery (respectively).
The best you can do today is run the Apple Diagnostics to see if any hardware issues are detected with the battery. If the diagnostics do not report a battery issue, then the "Service Recommended" only means that the capacity has dropped below some Apple pre-determined point (unknown what this point is). If the battery runs long enough for you and the diagnostics do not show a problem, then just ignore the "Service Recommended" battery status condition.
If the CalDigit dock caused damage to the laptop, then it is possible that it damaged the USB MUX controller chip which is involved with power/charging and USB. It is possible that this could cause the battery health to be improperly determined if there are other power related issues going on with the laptop. Or it may have been a device connected to the CalDigit dock that caused the problem (too many connected devices pulling too much power at the same time when reconnecting the dock?).
As for the dead pixels vertical line I cannot say. I would be very surprised if just connecting or disconnecting an external device would cause this problem unless the display was also touched during the process of connecting/disconnecting the cable and causing physical damage. But I have seen some very weird behaviors with these USB-C Apple laptops that have blown my mind so I cannot rule anything out when it comes to these junk laptops.
These displays are extremely thin and fragile so it doesn't take much pressure on the display or even a jolt to the laptop to cause the display to develop anomalies. It is also possible the display just failed naturally.
Unfortunately there is no way anyone here can say what really caused the display issue or even the battery issue (assuming the battery condition issue isn't just coincidence) and even physically examining the laptop may not provide confirmation. Only a tech that is able to perform board level repairs would be able to possibly determine what happened with your laptop, but those types of techs that really understand Apple hardware at that level are extremely rare and even then there may not be 100% certainty.
