what I don't understand is:
i made a perfect square clipping:

when i insert it into webplayer squared canvas it appears 4-5x bigger:

    height = container.scrollHeight;
    spinePlayer = new spine.SpinePlayer("incoming-animation", {
        alpha: true, // Enable player translucency
        backgroundColor: "#00000000", // Background is fully transparent
        skeleton: skeleton,
        atlas: atlas,
        premultipliedAlpha: true,
        //preserveDrawingBuffer: true,
        defaultMix: 1,
        showControls: false,
        animation: "animation",
        showLoading: false,
        viewport: {
            debugRender: true,
            x: 0,
            y: 0,
            width: height,
            height: height,
            padTop: "0%",
            padLeft: "0%",
            padRight: "0%",
            padBottom: "0%",
        },
        success: function (player) {
            console.log("Explosion animation loaded successfully");
            spinePlayer.animationState.addListener({
                complete: (entry) => {
                    //emit('trigger-bombs');
                }
            });
            // Set initial animation speed
            spinePlayer.animationState.timeScale = 1;
        },
        error: function (player, reason) {
            console.error("Failed to load Spine animation:", reason);
        }
    });
DOM element is:
<canvas class="spine-player-canvas" style="display:block;width:100%;height:100%" width="945" height="945"></canvas>