Titus 3:5
(5) not by works of righteousness which we did ourselves, but according to his mercy, he saved us through the washing of regeneration and renewing by the Holy Spirit,
Compare with the story of Naaman, 2 Kings 5:11-14 (WEB):
(11) But Naaman was angry, and went away, and said, “Behold, I thought, ‘He will surely come out to me, and stand, and call on the name of Yahweh his God, and wave his hand over the place, and heal the leper.’
(12) Aren’t Abanah and Pharpar, the rivers of Damascus, better than all the waters of Israel? Couldn’t I wash in them, and be clean?” So he turned and went away in a rage.
(13) His servants came near, and spoke to him, and said, “My father, if the prophet had asked you do some great thing, wouldn’t you have done it? How much rather then, when he says to you, ‘Wash, and be clean?’”
(14) Then went he down, and dipped himself seven times in the Jordan, according to the saying of the man of God; and his flesh was restored like the flesh of a little child, and he was clean.
This is symbolic of baptism. Naaman dipped (immersed) himself in water, and his leprous flesh became new like a small child - symbolic of being immersed in death and rising born anew. It was a simple enough thing for Naaman to do, but if he hadn't have done it he would not have been healed. Likewise being baptised by full immersion is a simple enough thing for us to do, so why wouldn't we do it in obedience?
When Jesus was baptised he said to John the Baptist, “Allow it now, for this is the fitting way for us to fulfill all righteousness” (Matthew 3:15), or as the Good News Bible puts it, "Let it be so for now. For in this way we shall do all that God requires". So I think we should be baptised by full immersion, if we have the opportunity.