The iPhone 17 Pro Max battery may influence the Galaxy S26 Ultra's battery design.

Leaked renders hint that the Galaxy S26 Ultra will be more enjoyable to use than the iPhone 17 Pro Max.
The Galaxy S26 Ultra will likely feature a 5,000mAh battery, the same as its six predecessors. Although this may disappoint some, the phone's battery life could still improve via more efficient components. The S26 Ultra may also support faster charging, which could compensate for the consistent battery capacity.
The iPhone 17 Pro Max could have improved battery performance compared to the iPhone 16 Pro Max, though its increased thickness might deter some users. A switch to lighter aluminum from titanium could reduce any issues with comfort.
The popularity of phones like the Galaxy S25 Edge and the speculated iPhone 17 Air show the importance of phone ergonomics. However, some users may accept a thicker phone in exchange for higher performance.
The iPhone 17 Pro Max and Galaxy S26 Ultra appear to be prioritizing different features. It remains to be seen which approach will be more successful.