@Ramiz
Unless the user has granted you "send as" permissions, you can't send as them - I'm surprised that this doesn't generate an error. That said, getting send-as permissions from all your users is not a practical solution.
If you don't want the emails sent from your account, consider using a shared mailbox and use the Office 365 Outlook "Send am email from a shared mailbox" action- this implies that you have permission to do so. Another option might be to use the Send an email notification action (green envelope icon) - I believe it will show as sent from "Power Apps or Power Automate".
I understand that you want to email send from the account of the person who created/modified the item - you just can't do so without getting permissions granted to you by each user who creates or modifies an item.