@MatthijsLVNL,
I think I understand what you what you want to do.
I assume your users are internal and sign in with thay M365 account. If this is the case then when thay fill out the form the form responce captures thair email address in the background. So when looking at forms and responces remember to get the user account information from their profile. There are pleant of videos that could help you with this, see one post below:
https://powerusers.microsoft.com/t5/Building-Flows/Microsoft-Forms-Get-the-quot-Display-name-quot-fro-Office-365/td-p/136474
I would keep your form as is, but write the data to a SP list so you have the data all in one place and can keep track of this for a managment point of view. Once the Shift 1 fills out the form the SP list is written to with the data and that flow stops. See above but subsitute the excel for a SP list.
The next flow will start with when an item is created which will start the creation of the PDF file with all the information in it and send this to the Shift 2 person. The flow ends.
https://powerusers.microsoft.com/t5/Building-Flows/Generate-PDF-from-SharePoint-list-item/td-p/195965
The above will genrate a lot of files in a persons onedrive so I would store the PDF file created in the SP list item then delete the file in ondrive. The above will involve the premium plan to use the word template action. I assume you can add this plan to the Shift Manangers plans.
The only issue I have is the shift leaders name, what happens if they fall ill, or are on leave, or there is an issue with getting to site due to an acident on the roads. Can the process work if this is the case. Does a mananger need to be copied in or deputy to the emails to make sure everyone knows about the issues. But that is whole different question altogether.
All my responces are ment to point you in the right direction in my view and not meant to do the work for you.
Regards,
Andrew