Hi,
You can solder 2x these breakout boards:
https://www.miravia.es/p/i1368157939064645-s2085778195771205.html?hybrid=1&data_prefetch=true&prefetch_replace=1&at_iframe=1&prevent_offline_jump=true&hHidden=1&fl_tag=1&srsltid=AfmBOor70PqdBv83NMje_rUH3YfMoIYZZjKpiAXwVUPIfCuF72vWt_XARIw
VOUT+ to Voltage.
VOUT- to Ground.
(to 2x of these connectors)
BAT+ to bat power.
BAT- to bat ground.
And these batteries, x2 (you don’t need the battery board, just the small ones I shown!):
I am sure all can easily fit inside.
