To keep a good car in good paint condition then you really need to go down the clay bar route.
Yes it can take a while, especially on a big lexus.
Yes it can also make you arms and back hurt with the effort.
But when you have finished and put a good wax over the top, you will not believe how smooth the paintwork feels. And getting those bits of crud off the paint that washing misses will make the paint last longer and look better.
Took me best part of 6hrs last time i washed, clayed and waxed my old girl, another 7hrs for the car after that
I hope sue don't read this, or i may have a pair of black eyes at our next meet