First world problems, literally
Plot twist: The next companion is a normal girl/boy who only dies once in their lifetime and has no remarkable back story but he thinks they’re wonderful because they are human and the Doctor needs reminding that you don’t need to be a mystery to be remarkable.
Even bigger plot twist: The next companion also isn’t in love with the Doctor or vice versa
Bigger still: The next companion doesn’t die, or lose their memory, or have their memory erased, or get locked in a parallel dimension….
At the end of their adventure, they leave, because the adventures over…