Showon field attribute targeting field from a group to root

Question

So this is an example XML:

<form>
    <fieldset>
        <field name="field1" type="text" default="" label="" description="">
            <option value="">JSELECT</option>
            <option value="1">A1</option>
            <option value="2">A2</option>
        </field>
        <field name="field2" type="text" default="" label="" description="" />

        <fields name="group1">
            <field name="field11" type="text" default="" label="" description="" />
            <field name="field12" type="text" default="" label="" description="" />
        </fields>

        <fields name="group2">
            <field name="field21" showon="noidea" type="text" default="" label="" description="" />
            <field name="field22" type="text" default="" label="" description="" />
        </fields>
    </fieldset>
</form>

I'm trying to toggle field21 in group2 when changing field1.

This just adds the current group:

 <field name="field21" showon="field1:2" type="text" default="" label="" description="" /> 

creates: data-showon="[{"field":"jform[group2][field1]"

This targets another field in another group, but i need the root...

<field name="field21" showon="group1.field1:2" type="text" default="" label="" description="" />

creates: data-showon="[{"field":"jform[group1][field1]"

This was just a try

 <field name="field21" showon=".field1:2" type="text" default="" label="" description="" />

creates: data-showon="[{"field":"jform[][field1]"

This is what i need: data-showon="[{"field":"jform[field1]"

I only found a similar question here, but that was a bit different and already solved: https://github.com/joomla/joomla-cms/issues/6744

I dont see if parseShowOnConditions is solving this.

There is a pull request making this possible, but it wasnt merged into Joomla 3.22: https://github.com/joomla/joomla-cms/pull/30850

Maybe there is another way of getting this to work.