Inserting a Redirect to a new page on an existing button

I need to create a redirect on an existing button of a contact form so that a "Thank you" page is opened after the user clicks on the "send" button.

Unfortunately my theme (Impreza with Wordpress Bakery pagebuilder) doesn't provide this option.

I'm only able to access the add manual code section of my theme for html (head) and css.

Is it possible to somehow modify one of these sections in order to get the redirect to my thank you page after the button on the bottom with these attributes is clicked?

This is the class of the button:

<button class="w-btn  us-btn-style_1" type="submit" aria-label="SEND MESSAGE">
<span class="g-preloader type_1"></span>
<span class="w-btn-label">SEND MESSAGE</span>

Thanks in advance!