My “HestiaPi” was made with a Raspberry Pi 3 and still uses an old image so it may work more smoothly than it had in the past for you.
On mine there was a folder in ~/scripts (sub directory of the pi username’s home directory) that contained a number of supporting scripts. On the version I have, the toggle for the sensor type is in /etc/openhab2/things/default.things.
The I2C data connections are SDA and SCL adjacent to the 3V3 https://pinout.xyz
With that working, the script HestiaPi came with read all the values, just doesn’t return them all. There’s two approaches to that issue that I’ve used along the way, either return all values read in text, then run a rule to put them in the respective destinations, or just query the sensor multiple times and throw out the unneeded items. The tossup boils down to how much processing you’re willing to do inside the Python script, and whether the overhead involved is affecting the sensor negatively. For the BME680 (which has a gas sensor as well), I did need to make that leap to reading all values together in one pass.
So in short, if the fundamental operation hasn’t changed from what I built upon, you’d be able to use the existing configuration to switch temperature (and maybe humidity, I forget if it was in the original files or if I added it) to the BME280, everything needed was included in the image. With that working, then switch focus to getting the humidity and pressure value in (and then that permits calculation of altitude).
I also suggest playing with the Adafruit BME280 instructions to get past the “the sensor is working” state.
I have temp/pressure/humidity working on my setup, so once you confirm what you’ve got looks similar still to what I used, we can build on that.