Charging two 3.7v 18650 batteries and powering two 9g Servo Motors connected to Arduino UNO R3

I just want to ask how am I going to power two 9G Servo Motors connected to Arduino UNO R3 using two 3.7V 18650 batteries and charging these batteries using TP4056 charging module at the same time? the TP4056 is connected with either a solar panel and 5V usb input to charge the batteries. I tried using only one 3.7V battery then using a 5V DC boost converter to supply the Arduino with 5V, but I am having no luck on powering both the Servo Motors as it would just slightly move, whereas if I were to connect the Arduino directly via USB or 12V power supply, it just works as it should.

It would really mean a lot if you can help me. Thank you so much in advance.

Post your schematic and a few images of your setup.