Ordered the kit, but in the meantime pulled the dryer out, ran it while disconnected from the vent and it's blowing out the back just fine. Vacuumed inside the lint trap as deep as I could and in through the vent in the back as much as possible. Took my leaf blower and very gently pulsed it in through the back of the dyer to see if I could get any more loose lint back up into the drum so I could vacuum it up again. Was a couple of tufts that came up at most. Vacuumed all in the dryer again and then took the leaf blower with a bag sealed to the end of it and blew out the vent to the outside. I left my phone recording outside so I could try to listen to see if it was muffled at all, but no, it was definitely loud enough that I probably pissed off some neighbors. Whoops. My vent immediately takes a 90 degree angle up into the attic from the wall with the dryer and then another turn in there somewhere back horizontally to go outside. I'd guess it's probably 20-30ft long?
I'm also wondering if I've purely freaked myself out just by fucking up dryer settings. I had bought a 100% cotton blouse because I need it for a choir concert this weekend. Threw it in a light wash and dried it. For some reason my brain thought cottons needed the delicate/low dryer settings, so that's what I ran the thing on, and after two cycles it was still wet and hot in the drum. Of course reading now, you're apparently supposed to put cottons on the cotton setting on the dryer which is higher heat. I may just be fucking stupid and got myself worked up over nothing.