So I just recently switched from FL Studio to Ableton. Obviously I use the ASIO driver for lower latency, but I've come across the issue that it doesn't seem that Ableton has an auto-close function as FL Studio does to switch between YouTube and Ableton. Does anyone have a solution for this? Thanks in advance.

I had a very similar issue. I ended up giving up on trying to find software solutions, and just buying an audio interface, it's worked out great for me. Although, if you can't be bothered to spend money on an audio interface, I believe you can use software like Virtual Audio Cable, but I ran into a lot of issues with it.