zoomx:
BME280 temperature overestimate surprised me but I discovered that datasheet talk only about pressure and humidity and not temperature and you don't find information about temperature accuracy.
Did you found sensors that are out of specifications?
I do not trust in accuracy numbers from datasheets (in general). The only uses for datasheets are i2c port and commands. One of the reasons is I use (mostly cheap Chinese) modules, not sensors itself. AHT15 and SHT85 are only exceptions when modules produced by sensor manufacturers. And modules can be, let's say, not perfect (for example chip overheating during soldering). So it is kind of not correct to compare module with sensor datasheet.
Just my personal impression from what I see during this project is:
DHT11 and DHT12 is not trusted in general absolutely.
AHT10 and AHT15 - also not trusted, slow and inaccurate, but maybe better than DHTxx
AM2320 - relatively not that bad (in compare to DHT and AHT)
BME280 and BME680 is always higher temperature and lower humidity (I suspect self-heating) I think those sensors are not for uncalibrated DIY projects)
HDC1080 - wrong (high) humidity
HDC2080 - wrong (high) temperature
SHT2x - OK
SHT3x - OK
SHTC1 and SHTC3 - OK
SHT85 - Perfect )
HTU21d and Si7021 is interesting because of SHT2x compatibility (i2c ports and commands), cheap, less accurate but still acceptable when no extra accuracy needed.
On the project test pages, there are .csv files published for each test so anyone can do the analysis and decide for themself which modules are accurate enough for their needs.
For example for test:
https://wiki.liutyi.info/display/ARDUINO/Test+3+v7+balcony+RH15-92+changing+humidity
There are files:
h_v7_test3.CSV
t_v7_test3.CSV