And therein lies the problem really. If you're playing 1 turn per day games, then an extra 50% on the time is a 12 hour wait, but if you're doing 4 turns per day, an extra 50% is only 3 hours. The latter is obviously quite a bit less frustrating and obviously more worth the wait, especially on games where it takes days to get a table started - even if all three players take an extra 3 hours, that's just over a day between turns for me, vs up to 5 as you say for yourself. So it's a very different value proposition and I understand your frustration.
There is a 2 turns per day setting, as well, which you don't mention, but I'm assuming may not work for you either.
The other point that someone on the forums once pointed out to me is that while 4 turns per day is "take your turn within 6 hours", it also gives 6 hours to each player, which in a 4 player game may mean that I actually only get 1 turn per day. It may be worth signing up for a game or two at a faster speed and see what happens with you only coming on once per 12/24 hours, however often you do - I suspect you'll find you don't run over anyway. And depending on how often you expect work to mean you can't take a turn within 8 hours, well, that is what the time bank is there for. While I get that you don't want to have to use it, if you're using it once or twice per game, by let's say 4 hours at a time, that's still a LOT better than someone consistently taking 1.5x turn time each game, and I don't think you should feel bothered about using it. Life happens, most players respect that. But the net result of using the time bank sometimes may be a less frustrating gaming experience for you.