I think the Titan should have other techs as requirements instead of being a standalone path.
I would have the initial titan's cost lower, equal or a bit bigger than a capital ship. A button like the capital ship's, which lets you buy up to 4 levels would exist, but it would be to upgrade the Titan to a full-blown one once the new technologies are unlocked.
For instance, it should at least depend on having starbase tech developed, following the logic that once you master massive hulls for starbases, you improve on adding massive engines to make a massive hull mobile.
In fact, I think there shouldn't be a Titan hangar, it should be a second option for the starbase builder ship.
The initial hull would have only weapons and move, but no hangars, skills or shields. It would get XP, but it would only level up to level 4-5, and would not be able to spend points on skills.
At least the first tier of each weapon type, hull and shields, as well as carriers and/or hangars, would have to be a requirement for the second Titan tech, which would enable upgrading the Titan to its full power, namely unlocking skills, shields and leveling up to the max. level.
There would be only 2 Titan research levels, but tied with several other tech requirements, either on tech 3-4, 4-5, or 3-5.