Hi @BB9 ,
Do you mean that you want to call a flow to send email with app's deep link to open a specific item in an edit form?
Do you mean that the ID in the deep link is dynamic value?
Could you tell me how do you get this dynamic value?
I assume that it is set to "ask in powerapps".
If so, I've made a similar test for your reference:
1)in flow:
trigger: powerapps
action: send an email body:
https://apps.preview.powerapps.com/play/2....e1?tenant......?ItemId=@{triggerBody()['Sendanemail(V2)_Body']}
//applink ?ItemId= ask in powerapps

2) in powerapps
(I use a gallery's OnSelect to call this flow, and use this gallery's selected as the dynamic ID value)
set app's OnStart:
If(Not(IsBlank(Param("ItemId"))),Set(var,Param("ItemId"));Navigate(Screen2, Cover))
//edit form is in screen2

set gallery's arrow button's OnSelect:
'410'.Run(Gallery1.Selected.ID)
//410 is my flow name

set the edit form's Item:
If(IsBlank(var),Gallery1.Selected,LookUp(deeplink,ID=Value(var)))
//if you open this edit form by using the deep link, the edit form will display the item that the deep link is related to.
If you open this edit form by gallery, the edit form will display the gallery's selected item.

Then if you click the arrow button in the gallery, you will send an email with this app's deep link. If you click the deep link, you will open this app and navigate to the edit form, the edit form will display one specific item.
Here's a blog about deep link for your reference:
https://powerapps.microsoft.com/en-us/blog/powerapps-deep-linking/
Best regards,