Performing the following (note the range of 10,000):

`importmulti '[{"desc": "sh(wpkh([aeee1e6a/49h/1h/0h]tpubDC5bVdaveQYxGFztMShFAjU637kKjrs9FD8ne1oHR7z8tLeQJExsaxWRVeSpcCcYMdp5ecf2LQhuVaeYFZ7YEpvWTJr4nDGUJrmuvLuTSsp/1/*))", "keypool": true, "timestamp": "now", "watchonly": true, "internal": true, "range": {"end": 1000}}]' '{"rescan": false}'`

takes many minutes. @achow101 reports a similar import taking 6 minutes on his machine.
{
    
    hashBlock = block_hash;
    
    nIndex = posInBlock;
}
int CMerkleTx::GetDepthInMainChain(interfaces::Chain::Lock& locked_chain) const
{
    if (hashUnset())
        return 0;
    return locked_chain.getBlockDepth(hashBlock) * (nIndex == -1 ? -1 : 1);
}
int CMerkleTx::GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const
{
    if (!IsCoinBase())
        return 0;
    int chain_depth = GetDepthInMainChain(locked_chain);
    assert(chain_depth >= 0); 
    return std::max(0, (COINBASE_MATURITY+1) - chain_depth);
}
bool CMerkleTx::IsImmatureCoinBase(interfaces::Chain::Lock& locked_chain) const
{
    
    return GetBlocksToMaturity(locked_chain) > 0;
}
bool CWalletTx::AcceptToMemoryPool(interfaces::Chain::Lock& locked_chain, CValidationState& state)