Difference between data types (int8 and float)

If you are short of 8k RAM on an ESP32, you probably wasted tons of memory to other things.

This is the result of a compilation for an e-paper weather display

Sketch uses 1018429 bytes (77%) of program storage space. Maximum is 1310720 bytes.
Global variables use 43180 bytes (13%) of dynamic memory, leaving 284500 bytes for local variables. Maximum is 327680 bytes.

I don't regard 327680 as very little.