If you are installing or upgrading Qlik DataTransfer on a Windows server with Qlik Sense Enterprise on Windows installed, Qlik DataTransfer must be installed with the Qlik Sense services user used in the Qlik Sense installation.
We actually made it work with a different account on the same machine
If the dedicated user is an administrator, you can log in as that user to install Qlik DataTransfer.
This is a bit misguiding: the installation process stops if the DataTransfer user is not an admin.
The policy SSL Configuration Settings must be set to only support ciphers in IANA format on the machine on which you are installing Qlik DataTransfer. If you are installing or upgrading to Qlik DataTransfer May 2021 or later on Windows Server 2012 R2, you must update the TLS Cipher Suite. The default ciphers included in the Windows Server 2021 R2 default security policy are not supported by Qlik DataTransfer May 2021 or later. The following cipher suites must be present: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
We did not need to do any of this on Windows Server 2016
You have professional access on that tenant.
The professional access is used to create the API token which is then used to connect DataTransfer. If the license is removed, datatransfer will (probably) also stop working. Might be smart to use a dedicated user.