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.
{
    WalletBatch batch(*database);
    for (const auto& entry : scripts) {
        if (!HaveCScript(CScriptID(entry)) && !AddCScriptWithDB(batch, entry)) {
            return false;
        }
    }
    return true;
}
bool CWallet::ImportPrivKeys(const std::map<CKeyID, CKey>& privkey_map, const int64_t timestamp)
{
    WalletBatch batch(*database);
    for (const auto& entry : privkey_map) {
        const CKey& key = entry.second;
        CPubKey pubkey = key.GetPubKey();
        const CKeyID& id = entry.first;
        assert(key.VerifyPubKey(pubkey));
        mapKeyMetadata[id].nCreateTime = timestamp;
        
        if (!HaveKey(id) && !AddKeyPubKeyWithDB(batch, key, pubkey)) {
            return false;
        }
        UpdateTimeFirstKey(timestamp);
    }
    return true;
}
bool CWallet::ImportPubKeys(const std::vector<CKeyID>& ordered_pubkeys, const std::map<CKeyID, CPubKey>& pubkey_map, const std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>>& key_origins, const bool add_keypool, const bool internal, const int64_t timestamp)