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.
/**
 * A CWallet is an extension of a keystore, which also maintains a set of transactions and balances,
 * and provides the ability to create new transactions.
 */
class CWallet final : public CCryptoKeyStore, private interfaces::Chain::Notifications
{
private:
    std::atomic<bool> fAbortRescan{false};
    std::atomic<bool> fScanningWallet{false}; 
    std::mutex mutexScanning;
    friend class WalletRescanReserver;
    WalletBatch *encrypted_batch GUARDED_BY(cs_wallet) = nullptr;
    
    int nWalletVersion GUARDED_BY(cs_wallet){FEATURE_BASE};
    
    int nWalletMaxVersion GUARDED_BY(cs_wallet) = FEATURE_BASE;
    int64_t nNextResend = 0;
    int64_t nLastResend = 0;
    bool fBroadcastTransactions = false;
    
    std::atomic<int64_t> m_best_block_time {0};
    /**
     * Used to keep track of spent outpoints, and
     * detect and report conflicts (double-spends or
     * mutated transactions where the mutant gets mined).
     */
    typedef std::multimap<COutPoint, uint256> TxSpends;
    TxSpends mapTxSpends GUARDED_BY(cs_wallet);
    void AddToSpends(const COutPoint& outpoint, const uint256& wtxid) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void AddToSpends(const uint256& wtxid) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);