Avoiding "First et al."
I'm going to advocate for using the style "[1] discovered that the sky is blue," even though you dislike it for grammatical reasons. I don't think that citations written like this need to be considered as parenthetical comments - they are just references, and can be used in place of the authors' names. Sometimes I will also see "Ref. 1 discovered that the sky is blue," which at least avoids putting the citation at the beginning of the sentence.

I agree that using "X et al." for an alphabetical paper is often misleading, and even though people are aware of this, it is difficult to avoid that bias. I have seen, in related cases, people refer to, e.g. "work from the group of Y" to avoid this. However, I do not recommend this, as it attributes more importance to the supervisor's contribution, and it is very easy to misunderstand the roles of people on a given project. (This also intersects with seniority, gender, etc. - big shot authors are more likely to be credited in this way.)

Author names as an acronym also seems quite useful, but I've mostly seen them used in cases where either A) there is a paper or idea that is classic in the field, or B) a single paper is a subject of focused discussion, and is discussed in depth by many other papers. For an example of B, there is the AMPS "firewall" paper in physics: https://en.wikipedia.org/wiki/Firewall_(physics) - they are also not compatible with giant author lists more common in some fields!