This study presents a dual-ended pumped 1.5 µm Er,Yb:YAl3(BO3)4 (Er,Yb:YAB) passively Q-switched microchip laser, designed to address the challenge of achieving high peak power and high repetition rates simultaneously. The dual-ended pumping method significantly reduces the thermal gradient within the crystal, allowing for higher pump incident power compared to single-ended pumping. Under quasi-continuous-wave (QCW) pumping conditions, the laser achieved a pulse energy of 14.33 µJ, a repetition rate of 470.08 kHz, and a peak power of 2.53 kW. Additionally, we conducted a detailed investigation of the pulse bifurcation phenomenon observed during the experiments, uncovering the underlying mechanisms and their potential impact on laser performance. The results not only demonstrate the effectiveness of dual-ended pumping in enhancing laser performance but also provide valuable insights into thermal management in Er,Yb:YAB crystals. These findings could serve as a foundation for developing more efficient and powerful Er,Yb:YAB lasers, which hold promise for applications in lidar, remote sensing, and range finding.