It's the waterdrop g3p800. I actually got it for free because the company accidentally refunded me when they sent me the wrong one at first lol. Most under sink systems I've seen are easy to attach and remove because the water supply is just a splitter that you screw on in between where your cold tap connects to the pipe from the wall. The drain fitting wasn't included for mine but I found the "Watts universal drain line to garbage disposal" adapter on Amazon which lets you connect a push fitting tube to where the dishwasher already connects to a garbage disposal. Typically the system I got includes a "drain saddle" where you are expected to drill a hole in the drain pipe and clamp a thing in that lets you connect the drain from the filter to the drain pipe and I wanted to avoid that (RO systems flush their filters periodically so the flush water needs a place to go). Beyond that, the only challenge is where to put the filtered tap if you don't have an existing hole up through the sink deck, but like I did in my old place, just having the filtered tap underneath the sink works fine if you don't mind your guests seeing under your sink.

I did a quick search and found there are countertop versions

https://bluevua.com/products/ropot-countertop-reverse-osmosis-water-system

For the waste, it goes to the septic, but I'm going to start collecting it since it is already been through all of the other filter stages before the RO,planing on useing it for water changes in the fishtank.