I've never used a sliding table and don't have the space to add one, but they ones I've seen from SawStop and Harvey look pretty useful. As do the dedicated sliders from Hammer and Felder.
Anthony, you would have the space for a slider if you did not go down the route of this YouTube presenter. I suspect that he is after clickbait rather than offering a useful design.
First of all, I do not work with sheetgoods and so chose a slider with a shorter wagon (the sliding part). Mine is a Hammer K3 with a 1250mm wagon.
The wagon can be fixed (with a catch) and then the slider becomes a traditional tablesaw. That would be a waste - my wagon is long enough to rip on (using a shopmade parallel guide) …
To the point - a slider has the wagon attached about 1” from the blade. This presenter has his wagon about 24” (or more) from the blade. Not only is this unnecessary, but the set up loses precision. He needed to remove the panel alongside his blade. I suspect that he did not understand this. The SawStop and Harvey accessory tables attach about 12” from the blade and are purely for crosscutting, and they, too, are best utilised as close to the blade as possible to do.
My K3 has a smaller footprint than the contractor saw it replaced several years ago.
I have a SawStop PCS that I'm mostly happy with -- I had some phantom brake triggers that seem to have been resolved -- but if I were to ever sell it, a K3 like yours would most likely be the replacement. My workspace consists of 1/2 of a small 2 car garage and you're right, the K3 (48x48) would be a perfect fit in my space.
Adding an accessory slider to my SawStop would result in a much tighter fit making it difficult to pull the car in.