Room Divider Living Area Experiences

That is correct, I just wanted to point out that Besta/Platsa are inherently designed more for an appearance like in the opening post. With Metod, you have to tinker more/use third-party manufacturers (for example, we also have So-Tech feet on ours).

I would definitely not "stick on" the wood panels... but build them in one whole piece from top to bottom. And then simply place the furniture in front of them.

Don't quite understand your question? I imagine exactly the same thing visually that I posted as a picture in the first post.

I thought you meant the so-called "panels," not the cabinets underneath. In theory, you can buy the cabinets anywhere else, or Ikea offers the option with many series to use a dresser as a bench/storage. That doesn't require much creativity, as the internet is full of Ikea hacks targeting exactly that.
Be that as it may: I would definitely work with Metod for stability.

that Besta/Platsa are generally designed to look like the image in the opening post. With Metod, you have to do more tinkering/rely on third-party manufacturers (for example, we also have So-Tech feet on ours).

Besta is way too overpriced. I honestly don't know what you'd have to tinker with on Metod.

Metod is suitable .. it also has correspondingly different depth carcasses. You will mostly work with the 37 cm deep carcasses. They are then completely variable and can be equipped with doors, drawers, or pull-outs. Suitable front divisions are also available. The backside (i.e., the thin back panel) then has to be covered. This can also be easily done with fronts.

Kallax - as already mentioned - has a lot of air and nothing solid in the "walls." The inner area, that is the compartments, are chipboard panels. This is not comparable to Metod. But if it is supposed to look somewhat valuable in the entrance area, unfortunately Kallax is just "trash." This is also reflected in the price comparison between Kallax and Metod.

I happened to actually see a 4-unit Kallax standing at the gym today, and it didn’t wobble. Regarding material, IKEA is known for minimal material use; they don’t use a gram more than necessary. I have installed Metod kitchens several times, and compared to some competitors, IKEA still seems more like entry-level quality. Nevertheless, we have moved three times with a Metod kitchen and I would consider an IKEA kitchen again anytime. Therefore, it doesn’t matter to me whether there is "air" inside or whatever; what counts is stability, and that is definitely sufficiently present. I find the term "trash" unnecessarily disparaging, since one could see the opposite everywhere on the internet and every Kallax buyer would be considered a fool and the Metod buyer automatically smart. There are plenty of kitchen buyers who call IKEA Metod "trash," so this can only be viewed with nuance. I wouldn’t want the solutions in the pictures in my house anyway, regardless of the price; in my opinion, that never looks stylish and will end up on the quoted "trash" in the next 10 years, but that is just my own feeling. The price comparison does not serve as a parameter, otherwise Opel compared to Porsche would also always be "trash." I think there are many shades of gray between black and white on this topic as well.

In this respect, it doesn't matter to me whether there is "air" or something else inside, what counts is the stability and that is definitely sufficiently present.

No. The smaller the grid is (1x2 or 2x2), the more stable it feels. But stability is something else. Especially if you ever have a 4x4 at home, then you know what I mean. We have enough Kallax at home standing and hanging. Great for the kids (with matching colorful doors etc.). But simply unsuitable for the living room.

I therefore find the term "trash" unnecessarily derogatory, as you could see the opposite everywhere on the net and every Kallax buyer would be basically a fool and the Metod buyer automatically smart.

That's why trash is in "". These are two completely different products. The simplest shelf construction in the lowest price segment on one hand and a rather high-quality kitchen cabinet on the other.
And for a high-quality entrance area, Kallax is simply rubbish. That won't change either.

The price comparison is not intended as a parameter, otherwise the Opel compared to the Porsche would always be "trash" as well.

It's like the Dacia compared to the Benz. You get what you pay for.