What is "com.samsung.android.dqagent_SA_SDK" user certificate? Is it safe? My user certificates has the following: com.samsung.android.dqagent_SA_SDK.

It seems so strange, it looks like someone put it on there. Is that normal?
From the name com.samsung.android.dqagent_SA_SDK, looks like the certificate is installed and used by DQA (also known as Device Quality Agent), a Samsung system app.

From some reports (in German and Russian), the certificate will automatically be reinstalled if it's removed, presumably by the app itself, since it also contains the certificate (from the report of reverse.it)

While I cannot certainly determine if it's safe or not, at least it's related to Samsung's own system app, so the possibility of a rogue certificate is lower (though not 0%). However, looks like you can disable the app without any side effects.