This message was posted on behalf of Intel Corporation
While we don't recommend nor provide support for custom wireless integrations (as mentioned by Al Hill), based on your description it seems to us that you're doing everything right.
The issues you're experiencing may be due to some hardware limitation placed by your computer manufacturer, or a defective wireless adapter (dead on arrival unit, perhaps?).
Checking the support page for your laptop, the Intel® Dual Band Wireless-AC 8265 should be supported, as it's listed under the possible hardware configurations for your model. However, there are several "sub-parts" for each wireless adapter, and you may have purchased one that does not match your system, or was customized for a different computer manufacturer.
Intel® Dual Band Wireless-AC 8265 Product Specifications, Ordering and Compliance page:
Our best recommendation when looking to upgrade the wireless adapter on a laptop computer is to contact your computer manufacturer and purchase the replacement part from them directly. This is the best way to avoid compatibility issues.
NOTE: Any links provided for third party tools or sites are offered for your convenience and should not be viewed as an endorsement by Intel® of the content, products, or services offered there. We do not offer support for any third party tool mentioned here.