In this case, I am almost positive Larian just isn't providing those sales figures. Before I didn't spend more than a minute googling how many copies sold, so 22M may definitely be too high, but I would honestly still be surprised if Starfield outsold BG3 at all, even if 11.5M of Starfield's 12M players were purchases, and not game pass, which is a super generous estimate.
But I have more than a minute now, so let's look at steamdb. There are 4 analytics things that provide owner estimations there. The spread on these estimations is insane, ranging from 5.5M to 27.7M. But the two middle ones estimate sales at 13.3 and 14.9M. Both are higher than the 12M players Starfield has reached through both sales and gamepass. But. These are steam specific numbers for BG3. It also launched on GOG, though I'm sure those numbers are nowhere near steams numbers. More importantly, it also launched on ps5, and who knows how many copies sold there.
Or maybe the achievement extrapolation method is the most accurate and it's between 7 and 8 million copies sold. There is still a very good chance even those lower numbers are beating Starfield in overall sales.
Regardless, this is all some nebulous as fuck guesswork, but I feel like it's more likely than not that BG3 straight up outsold Starfield. And even if it did not, Starfield had years of hype behind it, and Bethesda has been one of the biggest names in gaming for many years now. Larian was a niche studio making niche games (yes, the D:OS series was quite succesful, I would stay say they were niche though) so the fact that they're even in competition with the Bethesda juggernauts these days is quite impressive for them.