How to hide Add New button for Sub-Grid on tablet?

Hello.

I need to hide Add New button for Sub-Grid conditionally to the form context (CRM 2016 On-Premise)

I`ve found few ways to do that using Ribbon Workbench (custom JS rule with checking Entity name, Entity rule, Form Entity Context rule).

But none of them works on Ipad.

Also I`ve tried to combine FormEntityContextRule with CommandClientTypeRule(type Modern) in one Display Rule, with the same result.

Can anybody suggest me how to achieve needed result?

Thank you in advance!