Frankly, it would be odd for a brand's halo car not to boast the best numbers on a key performance metric. You may well be right that Lucid jiggered the software a bit so that the Dream (Range, at least) edged out the GT on range.The AGT was slated to have the best range and now it is not. Given the 131mpge vs the Dreams 125mpge and all the different range discrepancies it appears they have hobbled the AGT in favor of a better Dream all way round.
However, it's interesting that they did this by bumping up the Dream range instead of lowering the GT range. (The GT number for all intents and purposes remains the same as the FEV test, as 1 mile of range could easily be in the range of variance between any two tests). What stands out to me is that they suppressed the peak power output of a Dream model from 1,080 hp to 933 hp to bump its range from 503 to 520 miles.
There's more than just software in play here. The Dream Edition rear motor is unique in using special metallurgy that gives it a 15 hp bump and an undisclosed, but more significant, bump in torque over the motor used throughout the rest of the lineup. So Lucid may have had more to play with in manipulating the Dream software to change performance characteristics than they had to play with in changing GT software.
You could look at this two ways. GT buyers have had their expectations of a range topper crushed a bit. Or . . . Dream buyers have lost the ability to get an extra 280 hp over the GT at a very small range penalty (517 vs. 503 miles). They are now forced into a decision whether to take more top power at a significant range penalty or accept considerably less power to edge out the GT range by a meager 4 miles.
At the end of the day, GT and Dream buyers are being confronted with frustrations that 99.9% of car buyers could only dream of having. Buyers of either car are getting a machine at the very cutting edge of EV technology with a level of luxury and features available only in today's best ICE sedans. There are no losers here.