Looks like several of us converged around a similar design. I've had mine built for over a month, with zero leaks or other issues. I'm using a small amount of chlorine for sanitization, and with my filter, the water is staying completely clear.
I have a Inkbird WiFi ITC-308 to run the chiller on a timer. It's worked well, and to keep it at 45°F, I only need about 45-60 minutes of chilling a day — all at night when electricity is cheaper for me.
Full build with links to parts: https://andrewconner.com/cold-plunge/
Happy to answer any questions.