To my ear, you have one lifter that’s knocking pretty good - both on initial startup for a few seconds, and also when warm. The fact that it doesn’t do it while the engine warms up makes me suspect that you have a lifter that is either bleeding down too quickly or not pressurizing fully as the oil warms up and its viscosity drops.
If I’m right, then unfortunately those lifters will need to come out again before it damages the cam.
If you take them out, replace them with either GM LS7 lifters or Morel 7717. I believe that Melling is the OEM manufacturer of GM’s lifters so you may find a set of those for a reasonable cost as well. Most important of all, throw those eBay lifter trays in the trash and replace them with genuine GM trays only. The cheap trays won’t hold the lifters firmly enough: