Solid color Layer does not work in PS 2020

It's a known issue:

https://community.adobe.com/t5/photoshop/no-solid-color/m-p/11568895

https://feedback.photoshop.com/conversations/photoshop/photoshop-2021-windows-cant-make-fill-layer-windows/5f9a513249d3ca3d56ba9d11

I wrote a script to work-around the bug:

// Add Solid Fill Layer via Color Picker GUI.jsx

#target photoshop

if (app.documents.length > 0) {

    getColorpickerColor();

    /* https://community.adobe.com/t5/photoshop/get-photoshop-foreground-color-as-rgb-value/td-p/9402156 */
    var fColor = app.foregroundColor;
    var R = fColor.rgb.red.toFixed(2);
    var G = fColor.rgb.green.toFixed(2);
    var B = fColor.rgb.blue.toFixed(2);

    /* Clean SL Code for SOLIDFILL layer */
    makeFill(R, G, B);
    function makeFill(red, Grn, blue) {
        var c2t = function (s) {
            return app.charIDToTypeID(s);
        };

        var s2t = function (s) {
            return app.stringIDToTypeID(s);
        };

        var descriptor = new ActionDescriptor();
        var descriptor2 = new ActionDescriptor();
        var descriptor3 = new ActionDescriptor();
        var descriptor4 = new ActionDescriptor();
        var reference = new ActionReference();

        reference.putClass(s2t("contentLayer"));
        descriptor.putReference(c2t("null"), reference);
        descriptor4.putDouble(s2t("red"), red);
        descriptor4.putDouble(c2t("Grn "), Grn);
        descriptor4.putDouble(s2t("blue"), blue);
        descriptor3.putObject(s2t("color"), s2t("RGBColor"), descriptor4);
        descriptor2.putObject(s2t("type"), s2t("solidColorLayer"), descriptor3);
        descriptor.putObject(s2t("using"), s2t("contentLayer"), descriptor2);
        executeAction(s2t("make"), descriptor, DialogModes.NO);
    }

    /* https://graphicdesign.stackexchange.com/questions/125917/how-can-i-get-an-rgb-color-using-photoshops-color-picker-instead-of-systemss */
    function getColorpickerColor() {
        if (app.showColorPicker()) {
            return app.foregroundColor;
        }
        else {
            return false;
        }
    }

} else {
    alert('You must have a document open!');
}

https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html

Have you tried resetting the Preferences? Within the General tab of the Photoshop Preferences is the button Reset Preferences On Quit.