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.
{
    uint256 hash = wtxIn.GetHash();
    const auto& ins = mapWallet.emplace(hash, wtxIn);
    CWalletTx& wtx = ins.first->second;
    wtx.BindWallet(this);
    if ( ins.second) {
        wtx.m_it_wtxOrdered = wtxOrdered.insert(std::make_pair(wtx.nOrderPos, &wtx));
    }
    AddToSpends(hash);
    for (const CTxIn& txin : wtx.tx->vin) {
        auto it = mapWallet.find(txin.prevout.hash);
        if (it != mapWallet.end()) {
            CWalletTx& prevtx = it->second;
            if (prevtx.nIndex == -1 && !prevtx.hashUnset()) {
                MarkConflicted(prevtx.hashBlock, wtx.GetHash());
            }
        }
    }
}
bool CWallet::AddToWalletIfInvolvingMe(const CTransactionRef& ptx, const uint256& block_hash, int posInBlock, bool fUpdate)