Question Help me fixing this arduino code

[zwtch_17]

For the last couple of months, I've been making a hot air station based on a OneWire YouTube video. I made my own PCB and simplified the construction. But one thing holding me back is that the Arduino code has errors/bugs. I did fix some sleep/reed switch issue; now the screen is flickering between the main and cooling screens. It is also affecting fan speed and heater control. The original code had no problem controlling both, but the reed switch code was reversed. So you can control it on the holder, but when I take it from the holder, the code becomes bugged and the heater temperature rises uncontrollably while the screen unresponsive. can you guys help me fixing it?

thank you.

Here is the code link:
https://drive.google.com/file/d/1mPPRUA2n2QjGQ0_JYfQvjZ6wkAEe5ky0/view?usp=drive_link

video of it flickers: