It's hard to justify Liquid Glass in general. The wastefulness of flat design (in terms of space) married with the visual excess of skeuomorphism, but without even providing any affordances (does the sidebar being raised give you any new information on how to use a sidebar? No).

If you're a designer at a top 10 S&P 500 company making 6 figures, you owe it to yourself to have some love for your craft. If a PM tells you to shove a UI style meant for an unsuccessful VR device onto desktop and mobile platforms, say no. Get your colleagues to say no. Make that PM read everything the Nielsen Norman group has ever written. Read it too.