Wiring smart switch, confused about mishmash of wires in wall box

I’m trying to install a smart switch to control my 3 outdoor lights. 2 wall lights and a lamp in the yard. The house was built in 53, so I assumed there wouldn’t be a neutral in the box, so I picked up a GE switch that doesn’t require one. The switch shares a box with another that controls the hall light. Upon opening it up I found something more complicated than expected. The left switch, which controls the outdoor lights has 3 black wires coming in and bundled down to one black wire into the switch. There is then a second black wire coming from the outdoor switch that attaches to the right hand switch that controls the hall light, and then that switch has a red wire AND a black wire coming in. To top it all off, there are 4 white wires taped off in the back of the box. Are those neutral? I’d like to replace the hall light switch as well, but I think I’ll need to get a different kind of switch as I only bought a single pole paddle switch. I’ll attach a diagram below of the setup. Can anyone help me make sense of what I need to do to wire the smart switch and a new right switch?