iio.conf 

http://www.orangepi.org/orangepiplus2/ 
https://www.armbian.com/orange‑pi‑plus‑2/ 
SoC H3 @ 1.2GHz[1]
 DRAM 2GiB DDR3 @ ?MHz (H5TC4G83AFR‑PBA)
 NAND 16GB EMMC Flash (in 2016 KLMAG2GEND‑B031 but now slower KLMAG2WEPD‑B031)
 Power DC 5V @ 2A (4.0mm/1.7mm barrel plug ‑ centre positive)
 Features
 Video HDMI (HDCP, CEC), CVBS
 Audio 3.5 mm Jack, HDMI, Microphone
 Network 10/100/1000Mbps Ethernet (Realtek RTL8211E), WiFi 802.11 b/g/n (Realtek RTL8189ETV)
 Storage �SD (max 64GB), SATA 2.0 (via GL830 USB‑to‑SATA bridge, +5V power on JST XH 2.5mm connector)
 USB 4 USB 2.0 Host (via FE1.1s hub), 1 USB 2.0 OTG
bme280 i2c temperature/humidity/pressure
/home/dpavlin/linux-gpio-pinout/overlay-load.sh /boot/dtb-`uname -r`/overlay/*h3*i2c0*

root@opip:/home/dpavlin/linux-gpio-pinout# i2cdetect -y 2
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- 76 --

Check i2c address in datasheet
Connecting SDO to GND results in slave
 address 1110110 (0x76); connection it to V DDIO results in slave address 1110111 (0x77)
root@opip:/home/dpavlin/linux-gpio-pinout# zgrep BMP280 /proc/config.gz
CONFIG_BMP280=m
CONFIG_BMP280_I2C=m
CONFIG_BMP280_SPI=m

root@opip:/home/dpavlin/linux-gpio-pinout# echo bmp280 0x76 > /sys/bus/i2c/devices/i2c-2/new_device
root@opip:/home/dpavlin/linux-gpio-pinout# [Sat Jan  2 11:43:58 2021] i2c i2c-2: new_device: Instantiated device bmp280 at 0x76
[Sat Jan  2 11:43:58 2021] bmp280 2-0076: supply vddd not found, using dummy regulator
[Sat Jan  2 11:43:58 2021] bmp280 2-0076: supply vdda not found, using dummy regulator
[Sat Jan  2 11:43:58 2021] bmp280 2-0076: bad chip id: expected 58 got 60
[Sat Jan  2 11:43:58 2021] bmp280: probe of 2-0076 failed with error -22

So it's not BMP280, but BME280.
Using https://www.raspberrypi‑spy.co.uk/2016/07/using‑bme280‑i2c‑temperature‑pressure‑sensor‑in‑python/ 
 I downloaded and modified for python3 bme280.py 
root@opip:/home/dpavlin# ./bme280.py
Chip ID : 96
Version : 0
Temperature : 24.65 C
Pressure : 998.4304559219445 hPa
Humidity : 41.458674890198445 %e

So let's try with correct sensor name
root@opip:/sys/bus/i2c/devices/i2c-2# echo bme280 0x76 > /sys/bus/i2c/devices/i2c-2/new_device
[Sat Jan  2 12:32:01 2021] bmp280 2-0076: supply vddd not found, using dummy regulator
[Sat Jan  2 12:32:01 2021] bmp280 2-0076: supply vdda not found, using dummy regulator
[Sat Jan  2 12:32:01 2021] i2c i2c-2: new_device: Instantiated device bme280 at 0x76

root@opip:~# apt install libiio-utils

root@opip:~# iio_info
Library version: 0.16 (git tag: v0.16)
Compiled with backends: local xml ip usb serial
IIO context created with local backend.
Backend version: 0.16 (git tag: v0.16)
Backend description string: Linux opip 5.10.0-rc7-sunxi #20.11.3 SMP Fri Dec 11 21:18:30 CET 2020 armv7l
IIO context has 1 attributes:
        local,kernel: 5.10.0-rc7-sunxi
IIO context has 1 devices:
        iio:device0: bme280
                3 channels found:
                        humidityrelative:  (input)
                        2 channel-specific attributes found:
                                attr  0: input value: 40775
                                attr  1: oversampling_ratio value: 16
                        pressure:  (input)
                        2 channel-specific attributes found:
                                attr  0: input value: 99.809761718
                                attr  1: oversampling_ratio value: 16
                        temp:  (input)
                        2 channel-specific attributes found:
                                attr  0: input value: 25350
                                attr  1: oversampling_ratio value: 2

collect using telegraf
root@opip:/etc/telegraf/telegraf.d# ../telegraf --config iio.conf --test
2021-01-02T12:39:39Z I! Starting Telegraf
> iio,host=opip,name=bme280 humidityrelative=39.934,pressure=99.801214843,temperature=25.66 1609591179000000000