Why can't you just wait a similar amount of time for the treasury ETF to amortize back to "par" i.e. rise in value?
Owning a vehicle that owns bonds isn't any different than owning them yourself in regards to how it behaves for rising/falling rates.
The primary differences come from fees and management decisions around what to buy/sell with inflows/outflows and the overall portfolio characteristics (average maturity/duration, coupon, etc).
If you don't trust a professional manager to make those decisions on your behalf, then you shouldn't own a fund in the first place. Basically, it has nothing to do with how the vehicle behaves in response to interest rates.