Can replacing power steering pump & r&p steering cause engine damper to break on a 92 Lexus SC300 3.0 DOHC

What on the engine damper broke(harmonic balancer)?

The R&P will not cause the damper to break unless it was not bolted down appropriately & somehow came in contact with the damper.

The power steering pump if not aligned properly may damage the engine damper

Both these case I'd say r pretty difficult for them to occur unless bolts were not replaced. Simply replacing the two parts u indicated should NOT have damaged the engine damper in any way.