I'm still using the same AA eneloops I used since I picked up my Steam Controller all the way back in 2015-2016. And I also used it with my 360 controller too. Just keeps chugging along being good for a month before I need to swap.
Yeah the PS4 battery life has been crap and I don't know why. Was finally able to replace Sony controllers with 8bitdo now that Steam provides support for the extra buttons to be mapped to unique keys and use analog triggers and gyro together. So been nice not having to spend money on the dualsense, which doesn't even have hall effects/TMR sticks.
My dream steam controller 2 would be the steam controller layout with the large circular concave touchpads in the top most position, better bumpers, two extra bumper buttons like the 8bitdo, 4 back buttons in total, alpakka quality gyro, and nice premium feeling material used for the shell.
But, they'll go with the Steam Deck layout if there is one, which unfortunately has not been good for using touchpads as primary inputs for my hands. Which has me hording Steam Controllers, since it'll likely be the only dual touchpad focused controller around. And hoping Alpakka comes out with a standalone gyro module I can stick on the Steam Controller to at least have the gyro component updated.