Low-Power Wide-Area (LPWA) provides long-range, energy-efficient communication for IoT devices. Previous studies have shown that the IP2LoRa module enables TCP/IP communication over Private LoRa, one of the LPWA technologies. Dynamic modification of their transmission control is difficult because TCP and UDP are implemented in kernel space. To solve this issue, we utilize QUIC, a new transport protocol implemented in user space, to enable communication over Private LoRa using IP2LoRa, and evaluate its performance. Preliminary experiments revealed that packet loss inevitably occurs during the handshake phase due to the half-duplex nature of LoRa communication, resulting in performance degradation. To address this issue, this study proposes an adaptive delayed ACK strategy that delays ACK transmission during the handshake and then sends back multiple ACKs in batches. We verify the effectiveness of the proposed method through experiments using actual equipment. Experimental results show that the proposed method eliminates packet loss during the handshake and shortens the communication time by about 50%.