Liquid Glass is not something that will significantly affect battery life, but there are media reports that the effect can be reduced in macOS 26.1 that's coming out soon.
There are options to reduce motion, in System Settings > Accessibility > Motion (reduce motion), and in Desktop & Dock you can turn off the Dock animations.
Regarding battery life, it is possible there are processes running in the background that are using significant resources. Check Activity Monitor, CPU tab, sort by % CPU to see what's running hard.
Activity Monitor User Guide for Mac - Apple Support
As for your requests, “We” are users like you and have no power to implement any suggestions. To have Apple consider your feedback, submit it here:
Feedback - macOS - Apple