I haven't been able to take much action on my issue between work, family life, and hunting, did get some additional troubleshooting in today after clogging the toilet with a massive dookie. At the point, I'm certain there's an issue with the toilet itself, and potentially the discharge down to the first wye. I turned both bath tubs hot water on full blast, then opened the cleanout plug on the last wye before it leaves the house. The main bath was draining/flushing fine, while the master bath line felt hot and full. The tub was draining as fast as it was filling, meaning it was getting past the wye from the toilet and into the main collection line. I'll get the supplies this week, but I suspect when I take it up, the seal/flange/wye will be clogged. I'm going to buy a snake while I'm at it and ream things out. Probably rent one for the main discharge line while I'm at it so I can confirm it's clear and put my mind to rest in that regard. Will report back soon.