Considering the iPhone 7 plus has 3gb of ram, will it get more updates than the iPhone 7 standard edition ?
How many updates do you think the 7 plus will get?
iPhone 7 and iPhone 7 Plus will have same software support, regardless if iPhone 7 Plus has more memory than iPhone 7.
The worse case is iOS 16 is the last version for iPhone 7. This is entirely possible.
Or iOS 17 would be minor update, like iOS 12 was. So iPhone 7 will get iOS 17 update. But this is up in the air now.
However, it is highly depends on one devices: iPod touch. The currently iPod touch uses same chip, Apple A10 processor and it is still being sold. If by the time, we have iOS 17 and Apple still selling this iPod touch, iPhone 7 WILL get iOS 17. If however, Apple decided to kill of entire iPod touch line, then iPhone 7 will probably stuck at iOS 16.
iPhone 7 started with iOS 10, updated to iOS 11, iOS 12, iOS 13, iOS 14, iOS 15, iOS 16. So iPhone 7 has 7 software update. This is more or less the same as iPhone 6s Plus.
So it is safe to assume iPhone 7 will stop at iOS 16.