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.
strFailReason = _("Transaction fee and change calculation failed");
                    return false;
                }
                
                if (nChangePosInOut != -1 && nSubtractFeeFromAmount == 0) {
                    CAmount additionalFeeNeeded = nFeeNeeded - nFeeRet;
                    std::vector<CTxOut>::iterator change_position = txNew.vout.begin()+nChangePosInOut;
                    
                    if (change_position->nValue >= MIN_FINAL_CHANGE + additionalFeeNeeded) {
                        change_position->nValue -= additionalFeeNeeded;
                        nFeeRet += additionalFeeNeeded;
                        break; 
                    }
                }
                
                
                if (nSubtractFeeFromAmount > 0) {
                    pick_new_inputs = false;
                }
                
                nFeeRet = nFeeNeeded;
                coin_selection_params.use_bnb = false;
                continue;
            }
        }
        if (nChangePosInOut == -1) reservekey.ReturnKey(); 
        
        txNew.vin.clear();
        std::vector<CInputCoin> selected_coins(setCoins.begin(), setCoins.end());