How do I keep up when technology keeps changing my trade?

Your trade has kept its worth because people always need to feel safe. Locks change, but that need does not. The relearning you are doing is not a sign you are falling behind. It is the price of staying useful in work that matters. Try to see the constant learning as part of the craft, not an interruption to it. Every good tradesperson before you had to adjust when the tools changed. You are doing the same thing. The nerves you feel are just proof that you still care about doing it right. Pick one new thing to learn well this month instead of trying to swallow all of it at once. Master that, then the next. Steady beats frantic. You do not have to know everything today. You only have to stay a little ahead of the lock in front of you.