Whatever it is, I still maintain that Fdev didn't need to put it in the Codex and supply all those extra clues in 2018.
If you go back to 2017-2018 just before the Codex was revealed this thread was virtually dead with up to days between posts and only the very most die-hard few Raxxla hunters still occasionally posting (or someone new that just heard about it dropping in).
If Fdev didn't want Raxxla to be part of the narrative they'd have continued the policy they already had going: Don't talk about it, don't mention it, don't say the word Raxxla in-game at all, etc. There would still have been the truly die-hard people searching, but everyone else would have (and mostly had) moved on.
Whatever happened, for whatever reason, Fdev went to effort to include a fully voice-acted entry on both The Dark Wheel and Raxxla in Beyond Chapter 3 - the Exploration release which came with all the new scanning tools and the Codex, and all the new features to find in space (anomalies, Lagrange Clouds, and such). Beyond was one of the most well received releases in Elite history, and the community was already hyped for the content, there was no reason whatsoever to include Raxxla in the Codex unless there was something to find.
We all know Covid screwed a lot up for most people in most of the world, but consider that started in 2019 and the repercussions are still being felt. It's entirely possible that there were great and grand plans for development over the next few years that didn't manage to take off or had to be pushed back.
Most recently the Brookes memorial tour dedicated a portion of the final beacon to Raxxla. They didn't need to do that, if they wanted Raxxla to die or to minimise it due to pandemic-delayed-development they'd have simply not mentioned it in the beacon. Much like the Codex in 2018, the Brookes beacon injected a bit of life into the search again.
The fact is Fdev have told us there's something to find, repeatedly. Brookes told us, Braben told us, the later team told us in the Codex by supplying more information and clues than we've ever had before. It was then included in the Brookes tour beacon last year.
So, whatever Raxxla is, whoever knows at Fdev, it seems pretty clear to me that there is something we're supposed to be finding.