Hi there @Lipp!
Don here from Shopify.
Thanks for sharing your query with us here on our Community forums.
There are a number of apps in our store that would allow you to set up this kind of 'request a quote' situation for your products you can check out here in our app store.
As with all third-party apps in our store, you can reach out to the developers directly with any support queries you have by using the contact details listed there on the app store page.
For an alternative, there is coding customisation you can put in place that would replace the add-to-cart button with a contact link instead that sounds like a good match for your requirements.
Check out the options above, think about which you might prefer, and let us know here if you've got further questions at all.
Would you just be looking to apply this to some of your products, or all of them?