Thanks for the replies. So its most probably the quality of the Doit esp32 board.
However i have no explanation why the sntp sync started to fail on all of them.

I have created 4 metering stations in my rooms measuring temp, co2, etc. 2 years ago. Recently i started observing some strange behavior in 3 of them - uart returning error checksums in the one reading from mhz19b sensor, other is crashing or cannot set time using the sntp lib, the third is somethin...

Well, i dont know whats been changed in the master in the last sever hours but it fixed it.
Additionally i had to put the include in extern "C": Please fix it in the repo

Any help please? I am stuck at this all day. The esp_netif component seems to be compiled but can't be linked. I tried all combinations to include headers and REQUIRE components.

Well, i found the problem. I've used the esp_netif_t type in a wrong way. Now i have another problem, i cant link anything from esp_netif . The linker complains against anything netif related: /home/anio/.espressif/tools/xtensa-esp32-elf/esp-2019r2-8.2.0/xtensa-esp32-elf/bin/../lib/gcc/xtensa-esp32-...

I just changed to v4.1 and my project is a complete mess now :) I am looking in the compilation errors and replacing 1 by 1 but it's a pain. It's hard to search in the documentation because I don't know what to search for. It might be good if you write some article about it because this is a big cha...

I cannot understand this porting to Arduino at all. Why people want to wrap everything in Arduino environment?

Have anyone tried SP6205EM5-L-3-3 or MCP1726-3302E/SN?

Very interesting, i didnt know i can use serial link. Did you test it with different platforms? For example im trying to send from arduino nano to esp32.

Im stuck on this for 10+ days. So Ive decided to try it on two arduinos instead. Using all of the mentioned libs with their respective examples for tx/rx. The result is that probably either the receiver or the transmitter doesnt work I should have tested them early....