Indeed, although ISO 17025:2017 does not specifically require an appointment of a Quality Manager, nor a documented Quality Manual; it does not imply you cannot do so. You can include a quality manual as part of your documented management system and you can nominate a quality manager.
ISO 17025 specifies general requirements, to ensure competency. Your laboratory must establish a management system that suites your needs, to meet your objectives. In identifying suitable management, authorities and responsibilities, you can have one or more personnel performing the Quality Management functions. Likewise, when you establish processes and documents to meet ISO 17025 mandatory requirements, you could also include information in a quality manual, to describing the organization’s structure, the general requirements of impartiality and confidentiality and other processes that do not specifically require documented procedures. It is also a central place to reference mandatory documented procedures. A Quality Manual is included in the ISO 17025 toolkit. Have a look at the ISO 17025 document template: Quality Manual at https://advisera.com/17025academy/documentation/quality-manual/
It is important to understand the intent behind the revision, to help you implement ISO 17025 effectively. Have a look at the article ISO/IEC 17025:2005 vs. ISO/IEC 17025:2017 revision: What has changed? at https://advisera.com/17025academy/blog/2019/11/13/iso-17025-2017-vs-iso-17025-2005-key-changes-infographic/