Thanks for information.
My current proposal
AD5689R include two DAC.
First DAC setting Main level output voltage for example 0V,output is on summing amplifier.
Second DAC setting Transient level output voltage for example 2.5V.
Second DAC is connect to summing amplifier over switch (Probably external because internal switch is slow 4.8us vs 500ns for external switch)
This solution makes it easy to move from any level to any other with always the same slew rate.
One MCU eith the greatest probability any STM32F3 drive four of the same section section. Section works os one or four separate.
Slew rate seting is integrtion amplifier + 4 switch any as DG211 see picture , this make 12 slew level or
with 8 switch any as DG452 and 8 capacitors ove feedback on error amplifier in other section of design.
It works around both, but both are complex and due to the need to use better amplifiers or switche expensive solutions.
The goal was a simple and inexpensive design, with no Slew rate section there I have 10 amlifier as AD712, Unfortunately, the ad712 is about $ 4 in Europe (TME or Farnell)