Marvel's "What If...?" series has come to a close. An interesting look at what could have happened in the Marvel Cinematic Universe had things been slightly different, the series inspired a lot of fans with its invovative retellings of certain shows and films. It was a sleeper hit for Marvel, who saw it go three seasons before they pulled the plug. Due to its success, as limited as it was, some fans in other franchises want to see their own version.
Including, but not limited to Star Trek. There are fans who want to see Star Trek launch their own version of the show, tackling different scenarios in the multi-verse. The idea may have been Marvel's first, but the surge for this new concept to happen came after Star Trek: Lower Decks' 9th episode of season five. In the episode, 'Fissure Quest', various versions of Star Trek characters from across the multiverse came to help out a copy of Brad Boimler.
Seeing various versions of these characters inspired a push for Star Trek to further explore these alternate realities in their own 'What If...?' format. A format, that Star Trek would be wise to avoid doing.
Trying to expand your universe with the multiverse concept can lead to a convoluted story, with too many moving parts and a desire to possibly bail on the established universe for something more 'fun' or 'cool'. You could end up turning fans away due to the complexities involved with telling the story, as well as turning fans away by showing them something better that they can never have.
So it's not smart to look into that type of storytelling, not when your prime timeline has had so much criticism levied against it for years. If there wasn't so much up-and-down quality with Star Trek these days, sure, maybe. There'd be room for the concept to work. But they have to start nailing quality Star Trek shows and movies consistently before we start exploring concepts beyond the prime timeline.
That said, there is a non-canon way to explore these concepts; in comic book form. Star Trek's IDW run is pretty succesful, all things considered. Instead of trying to sink in hundreds of millions of dollars into a television concept that may not land with the audiences (think Short Treks), you could invest a fraction of that into a new art and writing combo and launch a new comic series.
You could explore possible events that never happened through the eyes of a narrator like Q, ensuring a fun book that only the most die-hard Trek fans will read. Considering that's who would watch the show, you save money and don't overextend your resources on a gimmick that didn't work for one of the most profitable entities today (the MCU).