2 of those big bottles of bleach in your pool should add around 13ppm of cl which should be a good dose for your pool given your low cya. Keep testing and hitting it with bleach as many times per day as you can to try and keep the cl level around 12ish. The key is to sustain the high reading without letting it yo-you up and down. No such thing as testing and dosing too many times in a day. Also, continue to run pump 24/7.

Try those cl tests again. I don't think you have 4.0 cc. Remember FC + CC = TC.

Keep an eye on your pH. It is pretty low. Might want to add a little Borax to bump it up some. Maybe add 1 cup additions. Pour it slowly into the skimmer, breaking up any clumps. Wait a couple of hours and retest pH and add more if needed. Note that if your cl level is above 10ppm when you test pH, you'll get a falsely high pH reading, so do this test at a time when your cl is not high.

By the way, it is ok to add Borax and bleach at the same time. Not necessary to only add one and then wait hours before doing the other.

Repost after you redo the chlorine tests.