Well as far as new subscriptions go - it was the SECOND highest -- the highest number of new subscriptions was the previous year (2019) when STD S2 started (with the 1701 and Pike); and they're even following the exact same marketing structure as STP's first episode is available to watch in it's entirety on You Tube (much the same way they released STD S2's first episode on You Tube last year.)As soon as Picard was announced, I expected it would get the most viewers. I would've been surprised if it didn't. The other series will probably get viewership numbers similar to Discovery. Even as subscriptions rise, I think DSC's viewership and other series' viewership will rise accordingly. But Picard will still be watched more than any of them, if only because of who's in it.
In fact, I've been counting on Picard being the reason for more subscriptions since that means more people will have CBS All Access and they won't be able to hide behind "I'm not going to pay for CBSAA!" if they have it now. And then maybe they'll try out other Star Trek series, including Discovery, because they might think, "I'm paying for it, so I might as well see what's on there!"
Still being the most watched (180% more than STD S2's premiere episode in 2019 on the CBSAA app) is nothing to sneeze at.
The Bottom line is that it appears Star Trek in general is doing very well for CBSAA overall.