How to fix HC05 burning even after while using voltage regulator?
You said &quot;I should mention that I was using voltage dividers for both of the transmitter, and receiver circuit's HC05 Bluetooth modules.&quot;
Voltage dividers are not a good way to lower voltage for power components. The voltage output will vary based on load, and they also dissipate the excess voltage as heat, so you need high current resistors.
Post a schematic of your system with the specific batteries, regulators etc that you are using.