Did accretinary collisions during Earth's formation cause heat loss?
No. They generated heat.
The reason for the earth tilt is not fully understood, but it is generally believed it was caused by collisions with other planetary bodies during the earth's formation. It does not tilt because of its axis. The axis is an invisible line running from north to south through the center of the earth. This axis is titled probably due to the mentioned collisions.
The tilt of the earth at 23.45° is a result of collisions with large bodies during the formation of the planets in the solar system. The size of the bodies and the angle of collision determined the tilt and the rotation of the planets. Each planet has a different tilt with respect to the planet's plane of the ecliptic.