I just realized a boring alignment: alignment to the page does not include bleed 3mm?

Simply use an Object Style fot position, works perfectly. For an example look here:

https://creativepro.com/how-to-align-objects-in-indesign-using-object-styles/

You're shocked that Align to Page aligns to the page? 

Granted, align to bleed could be useful - but you can adjust for bleed anyway. 

And so could align to slug. 

I don't really know how to help you here - it's not a wonderment about how a feature, it's just a reaction to something that's expected behaviour. 

If you want to make a difference and suggest improvement the correct channel is here

https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests

You'll already find others there
https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests/suggestions/31242319-new-alignment-option-to-bleed

https://indesign.uservoice.com/forums/601021-adobe-indesign-feature-requests/suggestions/42751931-add-an-align-to-bleed-in-the-align-panel-options

It's already in request - add your vote and your voice. 

It could probably be scripted.

Something like this

function alignToBleed() {
    var doc = app.activeDocument;
    if (!doc) {
        alert("No document is open.");
        return;
    }
    
    var sel = app.selection;
    if (!sel.length) {
        alert("No objects selected.");
        return;
    }
    
    var dp = doc.documentPreferences;
    var bleedBounds = {
        left: -dp.documentBleedInsideOrLeftOffset,
        top: -dp.documentBleedTopOffset,
        right: dp.pageWidth + dp.documentBleedOutsideOrRightOffset,
        bottom: dp.pageHeight + dp.documentBleedBottomOffset
    };
    
    var dialog = app.dialogs.add({name: "Align to Bleed"});
    with (dialog.dialogColumns.add()) {
        var alignLeft = checkboxControls.add({staticLabel: "Align Left", checkedState: false});
        var alignTop = checkboxControls.add({staticLabel: "Align Top", checkedState: false});
        var alignRight = checkboxControls.add({staticLabel: "Align Right", checkedState: false});
        var alignBottom = checkboxControls.add({staticLabel: "Align Bottom", checkedState: false});
    }
    
    if (dialog.show() == true) {
        for (var i = 0; i < sel.length; i++) {
            var obj = sel[i];
            var gb = obj.geometricBounds; // [top, left, bottom, right]
            
            if (alignLeft.checkedState) {
                obj.move(undefined, [bleedBounds.left - gb[1], 0]);
            }
            if (alignTop.checkedState) {
                obj.move(undefined, [0, bleedBounds.top - gb[0]]);
            }
            if (alignRight.checkedState) {
                obj.move(undefined, [bleedBounds.right - gb[3], 0]);
            }
            if (alignBottom.checkedState) {
                obj.move(undefined, [0, bleedBounds.bottom - gb[2]]);
            }
        }
        dialog.destroy();
    } else {
        dialog.destroy();
    }
}

alignToBleed();