Flying Pigeon brake pads - change or not
Welp, you have 'stirrup' style brakes that pull radially against the rim and will have limited power compared to brakes that apply opposing forces to either side of the rim. There is a reason this design fell out of favor many decades ago.
You may be able to get better brake performance with the softest, stickiest pads you can find that fit, but the design really limits the performance you can expect.