Finally nailed the baseline drift handling in code for the CCS811 chip, datasheet is wrong or incomplete. CO2 experiments next.

[S1] CO2: 409ppm, TVOC: 1ppb, baseLine: 0x16BF (0x16BF), lErr: 0b0
[S2] Pressure: 100914.39Pa, Temp: 32.46C
[S3] External temp: 31.37C
Uptime: 46536s