Lotta questions here.
As of writing, SpaceX has not released any plans at building a larger Starship in the near future.
That said, there have been larger SpaceX concepts historically, such as previous iterations of what became Starship like the "ITS" (Interplanetary Transport System) which had a larger diameter and was taller than the current Starship before it was scaled down and redesigned.
Additionally, the current size of the Starship upper stage is not fixed. It's already been lengthened once, and there have been rumblings/Elon tweets that the different variants (HLS, orbital tanker, propellant depot) might have significantly different final lengths according to their mission purpose.
SpaceX is extremely unlikely to build a three-core "heavy" Starship
Elon has gone on record, multiple times, where he basically states that Falcon Heavy was a mistake in retrospective. Originally, the plan was "just slap two boosters on the side" but in the end, they ended up basically needing to redesign the entire center core from scratch due to the much higher loads on it. The center core, despite externally looking like a standard B5 Falcon 9, is very different and not just a regular booster with two mounting brackets on the sides.
Knowing what SpaceX knows now, if they want a larger rocket in the future, they'll likely just build a larger rocket rather than kludging together something in the way it wasn't designed.
Orbital refueling will become and likely will remain a cornerstone of beyond-Earth space exploration
You ask:
will starship be able to finally travel to Mars or the moon without in orbit refueling
and the answer is, pretty solidly, no. Orbital refueling isn't just some "hack" that they're trying to implement until they can do without, it is fundamentally instrumental to the entire system and architecture. "Get rid of orbital refueling" is not a goal that SpaceX has (or will have) because from a rocket-equation perspective, it is just unbelievably advantageous and Moon or Mars missions without it at the scale they're planning is just completely unfeasible.
Yes, orbital refueling adds some "complexity" to the system, but ultimately, SpaceX are wagering that it will be worth it.
For example, could you build a car that can drive from New York to California and back (6000 miles) without refueling a single time? Sure, it wouldn't be easy, but if you put a couple engineers on the task and construct a car that's basically entirely fuel-tank by mass, it could be done. Still, it would be hard, expensive, and should only be done if there are no other options (this is current lunar and mars exploration). If we can refuel on the way, well, then why not do that?
Do we even need a larger launch vehicle?
Starship is big, and the amount of payload it can put into orbit is enormous should it operate at the parameters that SpaceX is targeting.
In fact, it is so big, that it has no current purpose. There are a lot of people dreaming about what could be done if we had one, but the current space launch market is already served quite well. In fact, the only major near-term "customer" of Starship launches is SpaceX themselves for their Starlink business, and beyond that, the only other real customers are either only purchasing a couple rides (NASA / HLS) or doing one-off missions (Dear Moon)--neither of which are going to get anywhere near the aspirational capacity of the Starship launch system.
A hypothetical "Starship Heavy" just wouldn't have any payloads to lift, and even if someone wanted to put something into orbit that a single Starship couldn't do, it would likely be easier to simply assemble whatever you are building on-orbit in modules or whatever.