Hi @markushock,
In such a scenario, you could add two Flexible Shipping methods to your shipping zone. With DHL and Hermes as their shipping method titles.
https://wpdesk.me/tg/chrome_ItsDdDQAwV.png
Then add Shipping Cost Calculation Rules with conditions based on price.
https://wpdesk.me/tg/chrome_lWaecvUJY2.png
As a result, you will be able to select these shipping methods when your cart totals exceeds 30.00 €.
https://wpdesk.me/tg/chrome_xkoTV05Ite.png
If you already use separate plugins to display DHL and Hermes rates. We offer a Conditional Shipping Methods plugin at flexibleshipping.com/products/ to handle this case. Due to the fact that it is a PRO plugin, contact us directly at https://flexibleshipping.com/support/ for more information.
Best regards,
Tomek