Thank you for your reply.
As I can see on my Windows 10 computer, that path has been created by DevKinsta by default when it’s installed: \Users\[user]\AppData\Roaming\DevKinsta
(mine is under the: C:\Users\iagus\AppData\Roaming\DevKinsta )
And the WordPress files/folders would be downloaded and extracted/unzipped inside the “Site path” set in the DevKinsta’s settings - by default it’s set to: \Users\[user]\DevKinsta .
(in my case, the WP would be saved inside the : C:\Users\iagus\DevKinsta\wp - as I showed in my previous screenshot before)
Please kindly check your DevKinsta → Settings (look for the “Site path” section), and then open your Windows file explorer and go to that same path/subfolder (e.g.: C:\Users\yourusername\DevKinsta ), and remove anything inside the “wp” subfolder there (if any) and follow the step 2 and step 3 that I suggested in the previous reply? and see if that will help?
The same error you provided:
[ERR_CHILD_PROCESS_STDIO_MAXBUFFER]: stderr maxBuffer length exceeded
was also mentioned in that other thread , and the solution was the same (and was confirmed to be working by the other user there).
Hopefully it will be working the same for you 
Cheers,
Agus