Thanks much, Leo.
I spent the last few hours trying out and came to following conclusion:
As long as the esp is on a breadboard, it doesnt log into my network. Wenn I pull it out of it, it logs in.
So, I think the esp32 I own has massive Wifi problems when it‘s on a breadboard. I‘ll solder wires on it later this day and will come back…
See post #7
The pads between the crystal and the red antenna look rather close on your module.
edit
If that is the case, you may be able to unsolder the red antenna and, using the orientation in the above picture, resolder it only on the lower pad and projecting towards the left over the board edge. But also look at other potential solutions.
edit 2
The mouse bites on the module are a sure sign that it is likely to be from a bad batch.
To all, especially Leo,
Today, I got another Board, which unfortunately is also one with the known wifi fault, however:
This one gives Output. With the many hours troubleshooting, I don’t know whether it was my fault or not. I tried both boards soldered with wires and this one works.
Thanks so much for the help and knowledge, it means a lot for me as I going through some issues and these projects help me being focused. Now, I know much more for future projects.
Greetings from germany
Glad you got it running.
I already warned you for the problems with that board in post#7.
Almost all boards I got from Aliexpress (50) ended up in my rubish bin.
The boards I ordered through eBay were the better type and were just OK.
Then I moved to Seeed XIAO ESP32-C3 boards and all problems disappeared.
Those boards also run directly on a 3.7volt LiPo battery and have a built-in charger.
That could eliminate the bottom charge board in the lander too.
There is a trick to reduce WiFi transmit power to get these faulty boards working.
WiFi.begin(ssid, password);
WiFi.setTxPower(WIFI_POWER_8_5dBm);
Some say that not fitting a pin to pin21 also helps.
Leo..
Thanks much, I'll definitely look into the quality ESPs you mentioned for the next project, as much of a headache these caused. Interestingly, the board I'm using now works even through a concrete wall, through pure luck I guess; I will test the that code 
If you want to calculate the running time from your battery...
I just measured the current draw of the ESP32C3 Supermini in that OLED setup, with my code, powered with a 3.7volt battery connected to the 5volt pin >> 23mA.
Leo..
Yes! I chose those boards for a project I have been working on and they are well documented and have good build quality The antenna is a little fiddley. I would recommend them, and think that the small price penalty is worth paying for peace of mind.
They are supplied with a stick-on aerial, which have a good range.
I stick them to the inside of a plastic project box that the ESP32 lives in.
For the projects that live in metal cases I use a standard WiFi aerial.
They both perform better than the ceramic or printed aerials that small ESP boards commonly use.
Leo..
