Alternative quantity selection – cognitive load & space problem

I am working on a product where users are ordering rather large quantities. Or even better said: The amount that people buy varies wildly. Some order a lot, some a bit less. We are aiming at adding two more options.

Currently we have free range selection of quantity with either input field or plus and minus buttons. But since users select pretty well defined quantities (a full box or a full van!), we want to give those options to add that quantity directly.

What we currently have Current product module

Experiments I tried adding the buttons for box and van next to it, but it clutters things up a lot, and I find it hard to find the correct solution. Something else I tried is below, which is adding a kebab for alternative actions. And letting an panel slide-in with the box and van buttons.

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However, seeing the numbers of people ordering boxes and vans they both seem too much of a primary action to simply but them behind something.

Do you possibly see any other routes that I could take this?

Thanks a lot!