Hi Pavel,

Try

<field name="comment" attrs="{'readonly': [('state', '!=', 'submit')]}" force_save="1" groups="!base.group_system"/>

<field name="comment"  groups="base.group_system"/>

The "!base.group_system"  in Odoo restricts access to an element, such as a button or field, to all groups except the "Administration/Settings" group.
This means the element will not be accessible by the users who have Administration/Settings access

Hope it Helps,
Kiran K

I thought it was working fine for me, but it puts the editable field with any user, even though it doesn't have the group I put in the inherited view

 id="group_maintenance_petitioner" model="res.groups">
            name="name">Maintenance Petitioner
            name="category_id" ref="module_category_maintenance"/>
 

id="df_maintenance_work_order_form_inherit" model="ir.ui.view">
    name="name">df.maintenance.work.order.form.inherit
    name="model">df.maintenance.work.order
    name="groups_id" eval="[(4, ref('group_maintenance_petitioner'))]"/>
    name="inherit_id" ref="df_maintenance_work_order_form_view"/>
    name="arch" type="xml">
        name="employee_ids" position="attributes">
            name="attrs">{'readonly': ['|',('state', 'in', ('history','cancelled','posted')),('active', '=', False)]}