u/Lazy-Location-6766

I have a swimming pool that I just drained to do some maintenance and renovation on it. Unfortunately, it's begun to delaminate in small to large patches (think 15+ places in sizes of 1-10 square feet). There's also a few audible voids when tapping on the plaster. My question is this: is it feasible to just patch all of this, or is a complete re-plaster absolutely necessary? Really trying to avoid the more expensive option in the short term, but don't want to attempt a repair that won't work for at least a few years. Thanks.