I'm not exactly sure which I2C problems you guys are discussing here, but I found a solution / workaround for mine on another forum. Links can be found here:
viewtopic.php?f=19&t=5094&p=22403#p22403

Well, I decided to make my project even more stable yesterday evening and copied over only the 5 files 'stickbreaker' mentioned. That gave a bunch of compiler errors, so I replaced the whole Wire library with this one: https://github.com/stickbreaker/arduino-esp32 It has been running for about 20 ho...

Wire.setClock(10000) definitely works here. The command is accepted, but with no effect - I guess you DO observe a change in frequency after changing the clock speed with this command. Strange, I don't. As my problem is resolved for the moment (I reset the bus as soon as the RTClock returns impossi...

The story continued here:

viewtopic.php?f=19&t=5094&start=20

and seems to come to an end finally.

I would have wished for even clearer rectangle signals. As I'm only reading a RTClock and writing to the displays every second, I would not mind if that would run at only 10kHz, but like I said, I cannot observe any change on my scope after using Wire.setClock(10000); :( On the other hand, the probl...

That was here: https://github.com/espressif/arduino-esp32/issues/912
See what 'stickbreaker' writes.

The compiler (only) accepts Wire.setClock(xxx), but with my cheap DSO138 oscilloscope I cannot see a difference no matter what speed I set. I'm using the DS3231.h, LiquidCrystal_I2C.h and "Adafruit_LEDBackpack.h" (which are then using wire.h) and do not need to include the Wire.h to run them. So I'm...

On my ESP32's board, an AMS1117 is installed. It's current limit is typ. 1100mA when Vin-Vout=1.5V.
The biggest SMD capacitor reads "J107", but I could not measure or find out its value.

Ok, so I missed that you're eliminating your power converter(s) already. Alkalines should be able to provide 1A, by far enough to initialize Wifi (I read up to 800mA somewhere. Never measured >400mA, but I might have missed 800mA peaks which could drop the batteries' voltage below a working value). ...

I'm using a 3.3V Arduino Mini (8MHz) with ripped-off voltage regulator and power led, which I supply by two Alkaline batteries connected to the 3.3V VCC pin directly. In deep-sleep, this should last for 57 years. When waking up, it powers a step-up-module via mosfet to send a high-power 433MHz ping,...