ok, main thing here is that sometimes too much detail is a bad thing. Your displacement map is a 2000x4000 image which is fine, but youve told octane's displacement to use a resolution of 8000x8000. This means the displacement is going to start showing the lower resolution of the image in the geometry. Lower the resolution of the displacement to 4k or 2k, then on top of that add in 2-3 pixels of gaussian blur below to give it a little more chance at being smooth.
Next you can bump up the AA filter size a little. The default is 1.2 pixels wide, youll be fine with 1.3 or 1.4
Then I actually lowered the reflection depth down from 32 to I think about 10. Your letters are reflecting each other, making reflections of reflections. This wouldnt be so bad, but...
... your glass is too perfect. With 0% roughness you dont have glass, you have the most pristine diamond in the world. Ive taken the greyscale displacement map and piped it into the roughness of the glass, this way only the lettering will get a slightly rougher/softer finish. Its then dialled way back by setting the mix value of the roughness channel to 0.02 so it only affects it very slightly.
This gets me from here to here