Reinforcing framing for installing a traditional AC unit in a sliding horizontal window

Hey all, Tried to look for past posts on this but most are looking for a solution that isn’t framing, which isn’t my problem. I am looking for advice on additional framing reinforcements. My fiance and I need to install an AC unit in our bedroom and we have horizontal sliding windows. A quiet unit is a non-negotiable. That limits our options in the realm of casement AC units, and I’ve written off portable AC units almost entirely. (Due to the noise as well as the vast inefficiencies compared to a traditional window unit). I thought of the solution of building a frame for our AC unit almost immediately. My fiance doesn’t want to do this as he’s concerned about our cats somehow knocking the AC unit out of the window and/or breaking the frame and escaping. To his credit, our cats are fucking menaces. One of them is an agent of chaos and the other one has unnatural strength and intelligence for a cat. If they combine forces and set their mind to it they can do some crazy things. A few additional reinforcements are not a bad idea - ideally we're shooting for zealous toddler levels. I’m confident we can create a safe and sturdy frame for an AC unit for our window. I've brainstormed multiple reinforcement ideas, but I feel like there are probably simpler and more effective reinforcements that can be implemented that I simply don't have enough building background to think of. Thus, turning to Reddit. The window frame is metal, about 23 inches wide and 40 inches tall. We are renting. We cannot access the window from outside of the building as it’s a multi-story drop. I can provide photos or more information if it would be helpful. We'd appreciate any reinforcement recommendations - or if you know of a quiet unit that will work in a horizontal sliding window without reinforcements. Any advice is appreciated, TIA.