@gavin67890 , thank you so much for your reply. Highly valuable information I totally missed when browsing the m5stack website. I was in a rush to get going and I was mixing up modules.
The https://docs.m5stack.com/en/product_i2c_addr is especially valuable as I was struggling with those IDs.
My kit was using the SHT30 built into the base, while I was reading the docs and trying the code for the one with the SHT20. Having the exact same physical look was the main cause for my misunderstanding.
I really appreciate your help! Now I have everything up and running smoothly.