The Kalam argument is essentially that every action has a cause, and that an infinite set of cause/effect events can only stretch from an exact starting point into the future (e.g if yesterday you launched a rocket into space on an infinite journey). It proposes we cannot have an infinite number of events in the past because the current event will always be waiting for an infinite number of prior events to complete.
Any amount of events could logically occur, even an infinite amount of events, if they all occurred at the same time. The important clause in the infinite regression argument is that because we are looking for a cause of the universe these must be cause/effect events, so A must always initiate (but not necessarily complete) before B is initiated, and so on. No matter how small an amount of time elapses between the initiations of A and B it will always be above zero. Therefore it will always take an infinite amount of time to perform an infinite amount of cause/effect actions, because any number above zero (time) multiplied by an infinity is also an infinity. Effectively we end up waiting for an infinite past to expire before "now" can arrive, and it would seem, at least intuitively, that this cannot happen.
William Lane Craig (and thus Hamza) use this as an argument to claim there must have been an initial cause that was itself not caused. In this way we could have a finite starting point and can reach the event in question (in this case the big bang). If the initial cause was some intelligent agent that decided to create the universe then the first action occurred 13.8 billion years ago and took 13.8 billion years worth of cause/effect events to get to point when I would start to write this post. No previous cause is required because it was a decision that started the events from a fixed point and not a previous cause/effect event.
These proponents use the term "infinite regression of events" because they need to hide the fact that it is actually the infinite amount time that is the problem. They convert a non-action into a first action by invoking an intelligent agent which makes the decision to act. Using "total number of events" as a unit of measurement the sequence can be initiated with a non-physical event (a decision) and thus provide a termination to avoid a historical infinity. When using time as a unit of measurement the same trick cannot be employed, because there will always be an amount of time between the decision and the action, and also an amount of time before the decision itself. Using the terminology of events is an attempt to avoid the question "So how long did this intelligent agent exist for before creating the universe?"
When asked this question the answer always seems to be the claim that the agent is eternal. The use of the word "eternal" here is to avoid saying the agent existed forever, because that is an infinite amount of time and we end up with the same infinite regression problem.
The use of the word "eternal" instead suggests that the agent is somehow able to "exist" in a kind of timeless dimension, and in doing removes the necessity of it having to exist for an impossibly infinite amount of time before it created the universe. So here the proponents of this argument sacrifice the existence of time itself, and have it appear as part of the creation of the universe.
So now the proponents have argued that there is no infinite regression of events, just 13.8 billion years worth, and they have also argued that there is no infinite regression of time because the intelligent agent was without time. However this just leads to a different problem, did this agent have any choice but to create the universe?
In order to have free will one must be at a point where there is a choice to make from numerous options. In this case the options would be to create or not create a universe (putting aside the incalculable options of what form it should take). Importantly, to have free will, the agent must then be able to make a decision based on those options.
The problem is that you must have the options before making the choice, there needs to be a logical precedence in order for free will to work, it essentially boils down to cause/effect of an intelligent source where the cause is the choice and the effect is the intelligent decision that was made. That is where the problem is, to have cause/effect, even of an intelligent kind, you need time!
Without time either nothing happens, or everything happens at once in a non-deterministic way. How can an intelligence non-deterministically determine how to create a universe? Did the universe not spring into existence at all because nothing happens in a timeless dimension? Obviously not!
So if everything in a timeless dimension happens at once then this requires the decision to create the universe, to exist simultaneously with the choice of whether or not to create one at all, while simultaneously the universe is already in existence.
If this agent created time before the initial state of the universe in order to avoid the paradox of the universe seed both existing and not existing simultaneously, it just moves the problem to time itself. Time itself would simultanously exist and not exist in this timeless dimension, and then not even as an effect of an intelligent decision to create it.
Without time there can be no logical sequence of evaluating options, making a choice, and then actioning that choice. These are essential for the freedom of will and freedom to act. Without freewill and/or freedom to act this intelligent agent is impotent, its intelligence is redundant. Powerful non-intelligent events are called "nature", rendering the existence of the universe an unknown (and very perplexing) natural event.
With time in this dimension there can be no way this intelligent agent can exist for an infinite duration. Without time the agent is irrelevant.
One thing seems pretty certain, and that is 13.8 billion years ago the universe was very tiny. There is no evidence to suggest the universe didn't exist prior to this time, we only know it existed in a different form. We don't even know it started to expand at that point in time, we just know that at a certain point in time it was expanding at a rate we could actually measure.
To even say there is evidence the universe was "created" or "began to exist" is wrong, and all of the logical fallacies built on top of this erroneous basis which require a complex reality of timeless realms are worthless on account that they are both unprovable and unfalsifiable.