Sorry this is so stressful - I think we've all been in your position (I know I certainly have) and it's a frustrating place to be.
You said that your brew ratio is always around 1:3, which means with the 14.5g dose you are currently using you're ending up with an output of around 44g. That seems like quite a lot to me, and depending on the fineness of your grind it may be that you are tasting some over-extracted flavours. These tend to be described as bitter or astringent*, which sound similar to what you're describing in the cup.
You also mention this in your post
23 seconds shot stops
Instantly weigh the shot of espresso and watch the weight drop a little
Why is the shot being stopped at 23 seconds? Is this you stopping it or the machine? If it's you, why? Are you stopping when the shot reaches a certain volume, the appearance of blonding or due to some other reason? You mention that after the shot stops you weigh the shot. I would run the shot into the cup/vessel whilst it is on a scale, so you can measure the output by weight. As Lancelot says, this is the only way to accurately measure output and therefore brew ratios.
Have you tried adjusting the grind to get a lower yield/brew ratio? I would recommend trying a 1:2 ratio and seeing whether that gives you more of the flavours you're aiming for. I personally wouldn't worry about blonding or normale/ristretto nomenclature at this stage - the main thing is to get coffee you're enjoying.
Try shutting off the shot when the scales hit 29g and see whether it improves things.
Are you able to post a video to show us what the shot looks like?
Hang in there! You'll get this sorted before long.
* https://baristahustle.com/blogs/barista ... o-taste-it