make sure to get cam holding tools, a set of slim wrenches, and NOT go gorilla on torquing down the main/timing cover while installing it. the cover is usually the most aggravating part of the install due to the tight space and the limited time you have before the sealant sets.
how long does the rattle last? do you have a lot of accessories come on at remote start? when was the battery last replaced/tested? crank speed can make a difference as it will affect the speed with which oil gets to the timing components. be sure to check and replace the VCT solenoids if you do proceed with the job. if you find the battery is draining, you might think about enabling Dark Mode to save drawdown while the car is off. this was discovered by a fellow member from Alaska.
high moly oils are also helpful in this regard. I too am experiencing brief startup rattle on my 2007 3.5L NA, and using Driven FR20 has significantly reduced the duration, eliminated it even on some startups. coming up on 1500 miles on it now. don't skip the oil changes, easy to do during these times.
a reference to get you started:
The Role Additive Chemistry Plays in Increasing and Decreasing Timing Chain Wear</a>
ultimately, replacement is the right path, BUT then you have to take a few small steps to prevent the situation from developing again