I suggest drinking bleach
Don't actually do that... drink antifreeze instead
It's a Hulu show IIRC. The only thing I know about it is it goes farther than Back to the Future when it comes to your mom being into you, which this is referencing
I always thought that the plot of BTTF was Spielberg not wanting to connect the obvious dots when the son his wife gave birth to grew up to look exactly like a guy she was really into a couple of decades ago.
But be that as it may Bella's time travelling is perfectly reasonable. She is a librarian and all librarians can time travel according to Sir Terry Pratchett. That's why "Don't meddle with causality" is the third rule of librarianship. The first two are of course "Silence" and "Books must be returned by the stamped date".
In her grief Bella violated the third rule. She put all the books MC expected to find in her house in the secret room where an L-Space portal formed. It's just that while she was trying to find out what happened to James she took a wrong turn and ended up almost two decades too far back. When she realised which time she had ended up at she fell into further temptation and tried to prevent her best friend Lynette's baby from dying at birth. It didn't go as planned.
The portal is still there because Bella hasn't figured out how to undo the mistake. All her attempts have only resulted in changing what Neil changed his last name into and what name he gave to the boy. And what the boy chose to do after getting to college. Now the portal is growing unstable and keeps randomly unlocking the door.
What Bella is thinking at the end of ep 11: "Oh shit, I'm going to have to explain time travel to non-librarians."