Normally, it does not receive signals and has more than 30 CraftingCombinator in place, which is a very large I'm concerned about the ScriptUpdate value that it shows (about 5.0 on average).

Also, I don't recall previous versions showing such a high TimeUsage value.

Is there any improvement that could be made that would reduce the TimeUsage while the signal is not being received?

Can I have the save where this is happening? In my tests the update time only started to climb over 10 ms once I build ~1.5k combinators, and even then it's only when they're all active, not when they receive no signals... They're not very realistic tests tho, so there may well be something I missed.