As long as they could obtain that Deityhood, those Deities at the time would have achieved their goal. Aside from this, they really didn't care what tactics were used.
As a result, given the situation at the time, they found that those plants simply couldn't be killed. If they continued, it wouldn't end well either, so those Deities naturally didn't hesitate much and came up with another plan directly at that moment.
After probing, those Deities discovered that forcefully confronting those plants wouldn't lead to victory. Under those circumstances, the plan to defeat the plants and obtain the Deityhood became infeasible.
However, obtaining the Deityhood and defeating those plants were originally two separate matters. Even with how strong those plants were at that time, it wasn't enough to deter the Deities' intentions. Because from the very beginning, those Deities never intended to completely destroy those plants.
