SOAP call to customermanagement service works in node + soap but not in Postman. Any hints about common mistakes?

I'm using node and the soap package. The code works and fetches the account info I need. This is legacy code which I'm trying to reverse engineer. When I call the soap packages' client.lastRequest, console.log('last request: ', client.lastRequest) I see the SOAP call that was made:

<?xml version="1.0" encoding="utf-8"?>
    <soap:Envelope
        xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
        xmlns:msc="http://schemas.microsoft.com/ws/2005/12/wsdl/contract"
        xmlns:tns="https://bingads.microsoft.com/Customer/v13"
        xmlns:q1="https://adapi.microsoft.com"
        xmlns:q2="https://adapi.microsoft.com"
        xmlns:q3="https://adapi.microsoft.com"
        xmlns:q4="https://adapi.microsoft.com"
        xmlns:q5="https://adapi.microsoft.com"
        xmlns:q6="https://adapi.microsoft.com"
        xmlns:q7="https://adapi.microsoft.com"
        xmlns:q8="https://adapi.microsoft.com"
        xmlns:q9="https://adapi.microsoft.com"
        xmlns:q10="https://adapi.microsoft.com"
        xmlns:q11="https://adapi.microsoft.com"
        xmlns:q12="https://adapi.microsoft.com"
        xmlns:q13="https://adapi.microsoft.com"
        xmlns:q14="https://adapi.microsoft.com"
        xmlns:q15="https://adapi.microsoft.com"
        xmlns:q16="https://adapi.microsoft.com"
        xmlns:q17="https://adapi.microsoft.com"
        xmlns:q18="https://adapi.microsoft.com"
        xmlns:q19="https://adapi.microsoft.com"
        xmlns:q20="https://adapi.microsoft.com"
        xmlns:q21="https://adapi.microsoft.com"
        xmlns:q22="https://adapi.microsoft.com"
        xmlns:q23="https://adapi.microsoft.com"
        xmlns:q24="https://adapi.microsoft.com"
        xmlns:q25="https://adapi.microsoft.com"
        xmlns:q26="https://adapi.microsoft.com"
        xmlns:q27="https://adapi.microsoft.com"
        xmlns:q28="https://adapi.microsoft.com"
        xmlns:q29="https://adapi.microsoft.com"
        xmlns:q30="https://adapi.microsoft.com"
        xmlns:q31="https://adapi.microsoft.com"
        xmlns:q32="https://adapi.microsoft.com"
        xmlns:q33="https://adapi.microsoft.com"
        xmlns:q34="https://adapi.microsoft.com"
        xmlns:q35="https://adapi.microsoft.com"
        xmlns:q36="https://adapi.microsoft.com"
        xmlns:q37="https://adapi.microsoft.com">
        <soap:Header>
            <tns:Action>GetAccountsInfo</tns:Action>
            <tns:ApplicationToken>actual_token</tns:ApplicationToken>
            <tns:AuthenticationToken>actual_token</tns:AuthenticationToken>
            <tns:DeveloperToken>actual_token</tns:DeveloperToken>
        </soap:Header>
        <soap:Body>
            <GetAccountsInfoRequest
                xmlns="https://bingads.microsoft.com/Customer/v13" xsi:nil="true">
            </GetAccountsInfoRequest>
        </soap:Body>
    </soap:Envelope>

I also output the URL:

https://clientcenter.api.bingads.microsoft.com/Api/CustomerManagement/V13/CustomerManagementService.svc?wsdl

When I copy these into Postman/Insomia/other API clients I get a 200 OK response BUT not the data I need. The returned XML is 1000s of lines of what looks like the API (Microsoft/Bing Ads API for their customer management service) definition.

I assume it's telling me that the request is wrong, so here, take a guide. But I don't know where to begin looking.

Anything I should look out for when translating Nodes' soap package -> a SOAP call within Postman?