get-balances.js

let addrs = new Set()

// avoid while(true) {} loops 
for(let bi = getReasonalbeStartingBlockIndex(); bi > 0; bi--) { 
  let block = await web3.eth.getBlock(bi) 
  if(stopCondition(block)) { 
    // block.timestamp < START_TIME
    break;    
  }
  if(blockMatch(block)) {
    // block.timestamp < END_TIME
    for(let hash of block.transactions) {
      let tr = await web3.eth.getTransaction(hash)
      addrs.add(tr.from)
      if(tr.to) {
        addrs.add(tr.to)
      }
    }
  }
}

for(let a of addrs) {
  let balance = await web3.eth.getBalance(a)
  // ...
}