Major image only lets you create one image of yourself

an object, a creature, or some other visible phenomenon

Note the singular there. Only one illusion of one creature can be created by the spell.

Does the purview of "some other visible phenomenon" cover me here? I'm not trying to "break" the spell necessarily; what I'm trying to create is a visible phenomenon.

No, it doesn't. Note that it says "other" visible phenomenon. That means visible phenomenon other than the two categories (object and creature) previously talked about. It doesn't mean "other phenomena" in the sense that you can ignore the limitations previously mentioned in the spell. The phrase is only there to allow you to create non-creature, non-object illusions (eg a rainbow or fog).

If major image was designed to allow this they would not have put the words "a creature" in the first line of the spell. Instead they would have said "objects or creatures or other phenomena". But they didn't and thus the RAW of this spell simply does not allow it to be used in the way that you want it to.

There is already a spell that does exactly what you want to do: mirror image

Mirror image says:

Three illusory duplicates of yourself appear in your space. Until the spell ends, the duplicates move with you and mimic your actions, shifting position so it's impossible to track which image is real.

This is exactly what you are trying to do with major image and since it won't work with major image you should just use it instead. The spell is literally tailor-made to achieve the effect you wanted. Mirror image is even a lower spell level than major image so you can get the same effect by using less resources.

Major image and mirror image are different spells that are designed to do very different things

Mirror image is a one trick pony; all it can do is create illusory duplicates of yourself to aid you in battle. Useful if you want that one particular thing, but not so useful otherwise. Major image is a very versatile spell that can be used for all manner of strategies both in battle and out. It can create illusory hiding places. It can create illusions of threats to scare off enemies. You can create illusion of treasure to set up a trap. You can create a single illusion of yourself to talk to the enemy leader and avoid exposing yourself to danger.

They are simply two spells with two different effects and ways they were designed to be used.

Regardless, the wording of major image explicitly shuts down what you are trying to use it for, it simply was not designed to duplicate the effects of mirror image.

^{Even if major image could duplicate mirror image's effects (again, it absolutely cannot), it would be strictly worse than mirror image in just about every way in doing the one thing mirror image was designed to do.}

^{1. Major image uses a higher spell slot}

^{2. Major image requires concentration (mirror image does not)}

^{3. Major image requires you to use your action to make the images move with you (mirror image does it for free)}

^{4. Major image disappears upon simple physical examination or an ability check. Mirror image requires each image to be hit with an attack.}

^{5. Major image’s illusions disappear at the same time. Mirror image only has the hit one disappear.}

^{There is simply no conceivable way that using major image the way you imagine it would be better than using mirror image instead.}

Like a performance script

The program referred to is just an ordered set of instructions. This is like a play and a bash script—in that bash with no input statements or system calls can’t have any variation in execution.

Programmed illusion has no allowance for interactions or inputs after the trigger that begins it, and no provision for detecting variations in its trigger either. It can only execute its pre-programmed visuals and sounds, insensitive to conditions, since it has no flow control features.

The real virtue of programmed illusion—and the meaning of its name—is that it can do things without the caster’s ongoing direction. Other illusions are generally static or require the caster to be an active puppeteer. The “program” in programmed illusion allows for a non-static illusion that can execute a complex series of activities without the involvement of the caster, something new in an illusionist’s arsenal.