Gyroscope: Many different gyros could fit depending on your needs, but let's add the widely used InvenSense MPU-6050 6-axis accelerometer and gyro. Its main interface is I2C, so we can connect it to the ESP32's I2C pins. Let's assume ESP32's IO21 is the SDA pin and IO22 is the SCL pin.

Buck Converter 5V to 3.3V: You could use a module like the MP1584EN, it's a simple buck converter from Monolithic Power Systems. This can take 5V down to 3.3V. The input would connect to the 5V source, and the output would connect to the 3V3 network in your circuit.

LiPo Battery Charging capabilities: For adding battery charging capabilities, you could use a module based on the MCP73831 chip from Microchip. This is a simple but effective single-cell LiPo charger. The - terminal of the module can connect to the existing GND net in your circuit, while the + terminal would become your new power net, replacing the existing 3V3 and 5V networks where needed. The BATT pin connects directly to the positive terminal of your battery, and can also connect to the VIN input pin of the MP1584EN module.