Just because timing marks on cam gears were correct when installing belt does not equal a car in timing.
You can spin the cam gears the incorrect direction to reach timing marks at tdc. Doing so will make it look right, but it is not. Motor is interference too. So, doing so could cause valves to hit pistons.
You did a lot of work. If OEM tune wont start car either it is not the tune. If ECM is communicating, allowing reads and writes it is not bricked.