Dear Marcus,
Microsoft Forms can't be customized and I'm sorry there is no feature in Microsoft Forms auto-refreshing the form to the submit page after completion. The only way is to manually click on "submit another entry".
Another workaround is to use the PowerApps form, If you need help on the PowerApps solution, welcome to post back and we'll help you further.
As our product developers are willing to hear users' suggestions and requirements for product improvements, I suggest you submit the feedback on the Feedback platform via the following link as well.
Ideas · Community (microsoft.com)
Please note the Feedback platform page will be loaded after some time based on the network environments.
You may access the page as follows to submit the feedback. You may use a personal account or another Microsoft 365 business work or school account to see whether you can submit the feedback or vote there.
Thanks for your understanding.
Have a nice day!
Sincerely
Cliff | Microsoft Community Moderator