The star washer is good for keeping low stressed bolt connection from coming loose, but on high stressed bolt connections the star washer can squish out some making the connection lose bolt stretch, torque and come loose. You do not see them on rod bolts, head bolts, flywheel Bolts and etc.
The captured spilt washers are good on the thrust plate bolts, they are made for that, if original. Medium thread locker would be a good Idea, they are not usually a problem if using good stock bolt with washer. If you have regular loc washers, they should be fine as they are not a high stressed connection, with thread locker.
Most timing sprocket, chain, problems are from improper bolt washers and bolt torque on cam bolt and crank.
you are using a thick hard washer on the crank bolt, the one in the pic is too weak.?
If any of this does not make sense just ask.