Does the present move at different rates relative to momentum- yet all matter shares one present “moment” whether it be long or short, OR does time simply act like a block, where matter can exist in any place in time with no real “present” existing?

Well, a complex question.

In short, Time is merely how we reference change. Change is the underlying reality.

Change could be change of position (motion), or change of temperature, colour, density, weight, radioactivity etc etc. Change comes in many forms.

Time has 2 core distinct contexts in how it references change (one word, 2 separate meanings):-

Time is the dimension of change. In other words we calibrate / measure change rate using Time. Example, Motion (changing position) is calibrated in , say, miles per hour. The miles quantifies the amount, the per hour (time) calibrates the rate.
The flow of change. All around us and within us there is change. The universe is expanding, the earth is spinning, tides turning, you breathing, atoms vibrating, quarks decaying..all examples of Change happening. And Time is a non-specific collective noun for all this change. Another example of a non-specific noun is Traffic. Traffic is a non-specific set of vehicles. We give Traffic physical attributes…it starts, it stops, it flows. But fundamentally Traffic doesn’t exist, only individual vehicles exist. Time is to change what Traffic is to vehicles.
So, fundamentally, Time doesn’t exist. Change happens, and is reference-frame (including quantum) specific.

So all change happens at individual, i.e. reference-frame specific, rates. There is no universal Time.

And the past changes to become the present which changes again to become the future.

Is it possible that something can be ‘outside’ of the ‘space time’ continuum?

Obviously Yes; abstract nouns, are outside the space-time continuum. Mathematics, justice, fashion, arts, science, religion…all abstract nouns that only exist in our mind.

But are you sure you know what the Space-time continuum actually is??

Space (in this context) is the dimension of (relative) position (hence xyz-axis)

Time (in this context) is the dimension of change (hence ‘rate’).

Spacetime is hence the merged dimension of changing position aka, motion.

So anything that is a ‘concrete noun’ (as opposed to an abstract noun) i.e. has a tangible reality – like a quark, or a table or a solar system – has a physical ()relative) position, and probably incurs change. And mostly will include change of (relative) position…most things in the universe (maybe all things) are experiencing motion, and all experiences relative motion (dimensions being reference-frame specific).

So anything with a physical presence will always be within the space-time continuum as you call it.

What would the 4th dimension look like to us?

Dimensions are abstracts…they are just how we measure, calibrate and index things. They don’t look like anything, they only exists in our minds.

Space is three sub-dimensions of height, width, depth, or the xyz-axis – which measure/calibrate relative spatial position

You don’t see the dimension…height for instance is just the measurement.

And Time (the so-called 4th dimension) is the dimension of change…it’s how we calibrate and measure Change. Eg Motion (changing position) is measured as, say, miles PER HOUR. The per hour but is the calibration of the rate of change.

So we don’t see the fourth dimension, we don’t see any dimensions. They are abstract models. What we see are the the underlying realities being measured, indexed – that is position, and changing position, i.e. motion.