First, as Zasul has said, you should probably try limiting your plans in the first place. Too many choices can lead to decision fatigue and your potential customers may end up choosing none at all. Perhaps you could simply to just "Plan 1", "Plan 2", "Custom plan" where with custom plan they can just speak with a representative and set up a plan that fits their needs.
The other solution that I would recommend, is to pick your "Top 3" plans either in terms of popularity or your most ecompassing (cheapest, middle, most expensive) and highlight those in the highlighted card layout and then stacking the remaining plans underneath, like this:
This will allow your visitors to view all of your options while hopefully reducing decision fatigue as they'll think they should probably just choose from the Top 3.
If you must display all plans at the same visual weight then I don't see any option other than condensing the cards as much as possible and then stacking them at the point when they no longer fit horizontally.