Dear odod,
There’s been an “align” feature for dynamics since last post on this thread. You can assign a keyboard shortcut to it. It works in Engrave mode, but you could select the elements (just as you described, it takes two keyboard shortcuts on my system pkus a third one to get to Engrave mode and a fourth on to align) in Write mode before switching to Engrave mode.
Hi Marc, thank you so much for the reply
i have tried the align feature, however it didn’t work properly on my imported xml score, even when i saved as dorico file, still no can do 
It’s not just XML. I find the Align Dynamics function often doesn’t work as I expect it to.
I generally just use Group Dynamics in Write mode.
I confess I’m like you, but I think it is because I got used to Group Dynamics before Align was implemented, and since I did not need it, I haven’t tried it really… But I cannot think it’s not useful, since everything is so well thought after in this program! I’ll investigate 
There are a couple of specific limitations with the Align Dynamics feature, but in general it does work as designed. The main limitations are that it does not work in Write mode (you have to switch to Engrave mode), and that it doesn’t align the dynamics between the staves of grand staff instruments like piano. If you find that it doesn’t work beyond these specific circumstances, please provide a minimal example project that reproduces the problem, and I’ll look into it.