If you honestly still think this is a port, then you are deluding yourself and I would definitely seek help for your inability to accept reality.

This game has:

Every prior character from every previous game, making it have a roster that is, so far, something like 20 more than it ever has been
At least 8 new characters (4 of which are echo fighters)
Multiple new stages and a total of 103 shown (Which is nearly double the past game's record)
As well as the ability to make any stage a battlefield clone in addition to final destination.
Significant changes to the base gameplay in the form of control and mobility tweaks
Some different move and vastly altered final smash attacks/method of getting smash attack
A return to the old style of Classic Mode
No mention of Smash Run or Smash Tour (but we might still get that)
The requirement to unlock most of the characters again (Something that was omitted from WiiU/3DS)
over 900 tracks, significantly more than the prior game's record
Dozens of new items, assist trophies, and pokemon.
Various other gameplay modes and features either not featured before or heavily altered from before.

And still more to come. We don't know what the hidden mode is (Spirits?), we don't know how we are going to unlock things or how many 'trophies' there are to collect.

The sheer volume of added or changed content is well beyond what any reasonable person would consider to be a port, and while there are some reused stages/characters, the fundamental differences are significant and there's really no argument to say that it's a port. Iterative changes/modifications have always been a staple of the Smash Bros series (and for that matter, virtually every fighting game ever; sports games, too), and nobody argued that Smash WiiU was a port of Brawl, or that Melee was a port of the original.

The graphics being indistinguishable to the untrained eye does not make this a port. If you honestly think so, then it shows that you see Graphics > gameplay and your opinion on the matter can be and should be summarily dismissed for lacking value or being outright wrong.

I am quite shocked this 'debate' is still going. It's not a port. Smash Bros Ultimate is a sequel, it just so happens to be a definitive sequel.

It's a port of my dream into reality.

I'm seeing a lot of posts across the Internet that essentially break down to: "By definition, if you think about it, a sequel is basically a port. So I am still right!"

This is pretty dumb anyway. Using assets already made for a previous game or whatever is just efficiency and has nothing to do with whether or not something is a new game or not. Why would a developer remake an asset when the new result will look exactly the same as the older one. Like, how much more detailed do you think they can make Kirby? Do you think they're remodelling 700+ Pokémon again and again and again for each Pokémon game?

Smash Ultimate is a new game as much as any other new game, and it blatently obvious from the very announcement.

Is Mario kart 8d a port.?if yes then same is with smash borsu.

I think we should keep in mind that we haven't seen everything the game has to offer. The game has around twice the number of stages as Smash on Wii U did, a lot more fighters, new multiplayer modes and it looks like we'll get a completely new single-player mode as well. What else does a game need to be considered new? The problem with Smash is that the amount of content they have created in the past is absolutely staggering: How should they be able to pull off a roster that is 50%+ new characters / stages? It's just not possible because past Smash games have featured almost every character and stage Nintendo has to offer.

Would Mario Kart also be a port if it had 40 new race tracks, 10 new characters, five new modes and new mechanics? Will Playstation All Stars PS4 also be considered a port if it only has twice the amount of fighters and stages compared to the original?

False analogy. A = B does not mean that X = Y.

A port is taking an existing program and adapting it so that program can be played on other hardware.

So, for example, Street Fighter 2 on Mega Drive is a port of Street Fighter 2 on SNES.

Street Fighter Alpha 3 on PSX is NOT a port of Street Fighter 2, Super Street Fighter 2 is NOT a port of Street Fighter 2. These are what you call sequels.

It feels like the accusations of it being a port are just concern trolling with this forced narrative of the Switch being a port machine. It has a lot of Wii U ports (for good reason--no one had a Wii U, plus portability is more than justification), but there are plenty of original games and Smash Ultimate isn't one of them anyway. The E3 Nintendo Direct ought to have put those accusations to rest for good.