Could this example help? https://bbs.espressif.com/viewtopic.php?f=61&t=560

建议你用 RTOS，明显比 nonOS 活跃很多 https://github.com/espressif/ESP8266_RTOS_SDK

应该有的，你可以问问是否有示例提供 https://www.espressif.com/zh-hans/company/contact/technical-inquiries-category

Could this example help? https://github.com/espressif/ESP8266_RTOS_SDK/blob/master/examples/wifi/simple_wifi/main/simple_wifi.c

AT command ends with a new line (CR LF). But some serial tool do not have "new line mode", maybe you can have a try with the secureCRT, it support "new line mode" (CR LF).

路由器一般会踢掉那些不活跃的 station，你可以试试从 8266 周期性的向外发心跳包，看是否还会掉线。

The AT firmware you used may be too old.. Maybe you can have a try with the ESP latest official AT. https://www.espressif.com/en/support/download/at

你这个版本也太老了吧。。可能是遇到api变更啦？可以查查release note，如果这么久远的记录还有的话。。
或者你可以考虑用新sdk https://github.com/espressif/ESP8266_RT ... system/ota

Not sure what the bridge AP is. But the ESP32 supports mesh, would it be the function you need? https://github.com/espressif/esp-mdf

It seems that ESP8266 does not have USB. But their latest ESP32-S2 can support USB.