You are pretty much dead on. The issue with full body is that it works great for a beginner, needs more volume at some point in progression, and then needs to be schemed pretty carefully as you get strong (ie you are not squatting 4x6 @80% sets across 3x a week and adding weight weekly or at least not for long). Like all things it gets individual too.
While from a pure muscle accrual standpoint it makes sense to focus heavily on pushing up the big stimulative lifts while eating big in the kitchen, you run into the issue above. The 2nd issue is that even if managed perfectly, it leaves precious little room for accessory work if there's any volume on the bigger lifts. Those 3 days will push your CNS limit. You can't add much more or needs to be a single issue/careful selection. Probably fine for an all around athlete base but not someone in most strength sports or a BBer - perceived need for overflowing variety in that population is HUGE. So more sessions and lower frequency for each lift. Now you get upper/lower run twice a week or 4 days but big lifts are 2x a week and even then you end up scheming volume with them as you progress.
Want to break it up more Chest, Back, Legs. This is in my mind the classic BBing split and it's stood the test of time - likely for reasons you cite and I added to, good balance and tolerable. You can get in some good volume on big lifts and put in a solid amount of accessory and isolation work plus CNS hit shouldn't be too bad unless you are really pushing things or loading the volume up on big compounds. Even then just add a rest day or so during a week and lower frequency some.
More than that is excessive for most but, for everything there is a season. Probably useful pre-contest or in other scenarios or for people who just like to be in the gym frequently. Who am I to say. If your arms suck and your mission for the next 3 months is to bring them up, maybe devote a day to them, sounds reasonable enough.
For what it's worth I most often do chest, back, legs these days as I like that balance and getting into the gym with decent frequency. I spent plenty of time squatting and pulling in some form 3-5 days weekly as well. Not saying I won't again but for work/life/fun balance it seems to fit well.