When she starts, quickly video it, discreetly if possible.
When she's having a calm moment and in good spirits, ask her for a grown up chat.
Show her the video of herself and ask her questions about it (what was going on here for you? What is making you cross here, can you explain? Does making that noise help you when you are angry? Etc) and give her lots of encouragement as she answers. Write down together what she comes up with in a fun way- bright pens, drawings, whatever.
Work with her, once she has highlighted her main issues, to write out alternative responses, and see if she can come up with any herself.
Example might be; "I get cross when we have to get dressed because I like my pjs"
Alternative to whining about it might be;
"When I feel angry with you about having to get changed in the morning, I will do a silly dance and wiggle to get my energy out!"
This isn't a quick fix and she needs lots of time to practise her new responses- thinks weeks and months, not days.
But, you are a) acknowledging that there are things in her life she dislikes and b) helping her develop ways to deal with them without resorting to whining which doesn't help anyone or anything, and ultimately, she still has to get dressed.
You could use a reward system on top, but start really small, like- "you talked to me in a calm voice- here's an extra story / episode of Paw Patrol" etc
At 4, she is capable of accepting and understanding that sometimes things just have to be that way- but she is in the behavioural pattern of responding with a whinge & whine now- it will take a while to break it- but you can definitely do it x