The 911 was first produced in 1963 with an air-cooled flat 6 engine mounted aft of the rear axle.
The 3 series, first produced in 1975, is a front-engine car with a water-cooled straight-4 and -6 (most commonly) water-cooled engine mounted in front.
So the first 911 was made twelve years before the first 3 series, is structured completely differently and has completely different engine technology.
The Model 3 was released 2-3 years before the Taycan is expected out, and has essentially the same layout: floor battery with front and rear electric motors mounted in about the same spots. They both have four doors with the same deep swoop down of the roof over the rear seats, flattened hoods that dip below the line of the fenders, etc.
The Taycan looks more like a Model 3 than any other electric car around, and since the Model 3 came first, it's reasonable to describe the Taycan in Model 3 terms.
It's a good design, functionally and aesthetically, and I'm certainly not faulting Porsche for these design choices. I've owned a 911 before and I've always appreciated Porsches - they have made many great cars, and the Taycan might well be another one. I hope that it is. But it does look a lot like a Model 3.
I have almost 40,000 miles on a Model 3 and from my personal experience with it and with other cars I've owned, including hundreds of thousands of miles on Porsche and Mercedes, the Model 3 handles the best. Air suspension will, I expect, give the Taycan a slight edge, but other than that, there's no magic dust that Porsche can sprinkle to make their car any different. Just putting the massive weight of the battery on the floor is enough to give both cars a big advantage over any ICE car.
You mention that the cars are in different classes - the only class that they don't share is price. The Porsche is predicted to cost between 2x and 3x the price of the Model 3. They're of comparable weight, size, power output, layout, etc.
You mention that the Model 3 has a poor interior - again, unless you work for Porsche or otherwise have access to as-yet unreleased photos, there are no released images of the Taycan interior. How can you know the interior is better? The Model 3 interior is simple, clean, and spartan, but I like it better than the E-class I drove before the Tesla. When I go back to the E-class, it feels fussy and baroque in comparison.
We know how advanced the Model 3 self-driving is, and it's constantly improving with frequent updates. It's really quite good. Will the Taycan be better? Perhaps, but at this point Tesla has had hundreds of millions of driving data to refine their approach and Porsche has not. Even if Porsche outsources from someone with much more experience, such as MobileEye. They're unlikely to be much better than Tesla. All of Porsche's money and many years of racing successes can't make software development suddenly leap ahead.
Finally, Porsche, in this video, is pushing the ability to run at "full performance" for a long time. That video, while very nice, didn't give any facts and figures about what that means. Tesla's had ten years and several generations of drivetrains to work out the kinks, including the overheating problems during track time of older Model S cars. When the Taycan is finally out and people can independently compare the two cars, I'll be interested to see of the Taycan is significantly better, but before that happens there's no reason to think that it will be.
Let it be resolved, then, that the Model 3 and the Taycan are in exactly the same class in every area except for price. I hope the Taycan is a great car and I'm sure it will be.