Can't play Variants on the App


The Apps are designed to work on phones and tablets.
The website works on desktops, laptops.
They are different. One historic difference is that the screen size for computers and laptops historically dwarfed the size available for phones.
I imagine that you might respond that you have seen tablets that are as big as a desktop monitor. That is interesting. However, most phones remain substantially smaller and it is complicated to add variants for only those that are big enough.
Every feature that gets built out takes time and money to build. Over the years, they have announced that they weren't then going to spend the money building more "variant" functionality for the apps because the number of variant users was too small.
Chess.com hasn't yet announced when apps functionality will be the same as that on the website. It will undoubtedly happen-- some day. The trends are clearly visible. (I decided to uninstall the app recently on my phone because the website kept trying to pull up the app.) However, it may be some time before it fully happens.
In the meantime, you can use a web browser on an Android phone to pull up the website. I don't know how well it works on an iphone.