I haven’t found one. Many YouTubers are more interested in specs, reviews, benchmarks for a specific make/model of device, not talking about broad concepts like wireless strategy, placement, roaming, RF characteristics, etc.

I studied many online documents, took several networking courses, referenced physics information about electromagnetic transmission, I even got certified as an amateur radio operator to know all I do. A lot of one-off searches for information. What helped me with that was going through, in detail, just about every configuration option on a Cisco aironet wireless controller. They expose almost every option and wireless specification for the administrator to configure. It’s far more advanced than anything from ubiquiti, or any other vendor. Most of the settings are fairly benign and probably should not be changed, so I get why that stuff isn’t available for most, but some stuff is rather useful to be able to change. I just went through it, option by option, until I understood what every setting, protocol, and option changed and how it affected wireless coverage and performance.

I’ve been working on my knowledge of these systems over the past decade. I have probably forgotten more than I remember at this point.