⚫ John uses both the Gematria and the formation of 'heaven' שמים (1Jo 5:7) ...three in heaven which testify) * Gematria of שמים = (3). Reducing the sum of the digit: 3 + 4 + 1 + 4 = 12 = 1 + 2 = 3. We do not use Gematria, we merely observe when it occurs in scripture.
Notice that שמים heavens without י creation is שמם desolation. The heavens were 'desolate' ( a metaphor for unproductive). God had not yet created anything.