WhatsApp considers these apps completely violate their conditions of use, which are accepted by each user when installing the official app, and that they also use tricks that violate the security of users, which is why it temporarily suspends the user's account. It is a kind of notice so that you only use the official app. If you don't, you will end up closing your account permanently.
The way to end the temporary suspension of your account is to stop using these unauthorized apps and use the official WhatsApp application as soon as the suspension time ends. However, it is possible to make a backup of the chats to pass them to the official version of WhatsApp.
I will explain how you can make a backup from apps like WhatsApp Plus or GB WhatsApp. If you have used any of these apps, you have to manually backup your chat history before downloading the official app from Play Store.
If you want to recover the chats, you have to wait for the temporary suspension to end. A stopwatch shows you the duration of the suspension. When it is finished, in GB WhatsApp, touch More options > Chats > Backup. Then go to Phone settings / tap Storage > Files. Find the GB WhatsApp folder and rename it to "WhatsApp".
Once this is done, download the official WhatsApp app, type your phone number and on the screen you will see "A backup copy was found", tap Restore and continue to use WhatsApp normally.
If you used WhatsApp Plus and saved the chat history, it should be automatically transferred to the official WhatsApp. In any case, WhatsApp does not guarantee that this process to recover the conversations will work, as these two applications, or any other, are not official.