Hello People! Hope you are having a fantastic time in your gardens during this Spring!

I have an about 2 meters tall Buddleia tree (shaped as) in the garden of my recently moved-in home. I don't know what type of buddleia is, but absolutely love the idea of attracting as many butterflies and all possible sorts of winged animals as possible. Although, the plant is full of dead brown flowers and I have been reading that deadheading shall be done as soon as flowers start to dry and pruning by early Spring. So, the question is: Shall I deadhead all dead flowers? Or shall I do not or maybe just some of them?

Good to have in mind that I have just started a veggies and fruits garden (which is actually my priority), so would deadheading now (consequently attracting or not butterflies and/or birds) influence positively or negatively on the growing? I am just a beginner in gardening, so basic tips would also help a lot.

Any help will be highly appreciated! Thx!