Hi @HammmerOz,
Not directly. Forms cannot use table lookups or buttons that I know of.
Your best bet would be to have automations on form submit. A column could be added that is a button and on each new form submission have it press the button. This button could run the validation check and add to the results table. In the event of a duplication you would email back the user to let them know, as long as the form holds a way to identify the user submitting and the email to notify.
As I was about to submit I did have another thought. I previously helped with another forum post where they wanted to allow Form users to add new options to a drop down list that would become available to all other form users. Essentially it would build over time. While you cannot use filtering on this it could perhaps be modified so that the list contains existing results and the user submitting has to check to see if their new submission isn’t already listed. You can find it here.
If you want help with setting up something like this I would recommend creating a new post and we can go from there.
I hope that this info is useful.
All the best
Dale