My TTGO cannot connect with ABP to V3

I don’t have any problems with ABP on v3. See Disable Frame Counter Checks in V3 - #60 by descartes

So how will your device cope when you need it to hear a downlink - discarding OTAA isn’t a solution, it’s ignoring a problem

It’s not available anymore, TTI have moved on, TTS is bigger, smarter, more compliant, more robust, still free to use.

That’s nothing to do with LoRaWAN

In the tangential way that it’s part of the LoRaWAN spec, a fundamental part of it, and so LMIC needs to keep the f_cnt.

Frame counters are so fundamental that your apparent lack of motivation to go and learn about them but to throw questions on to the forum indicates a bit of a loss leader for all those trying to help you as we’ll all be answering questions forever.