I'm fairly certain that I read this somewhere between 2016 and 2019. The protagonist, a female, gains the ability to travel back in time somehow, and embarks on what ought to be a get-rich-quick scheme, grabbing what is a common item in that time period and burying it to be dug up in the future. However, first she runs into issues where extrinsic events result in the buried item not remaining safe, and as she starts tweaking bits of history to ensure that she gets her artifact safely back (seemingly invoking dangerous amounts of Butterfly Effect), she eventually learns that the form of time travel she's doing results in timelines splitting, which means that the odds are fairly low of her returning to a timeline where the object is still there, but also meaning she has little reason to fear her other changes resulting in, say, the United States turning into a theocracy.
I either read this as an ebook or listened to the MP3 audiobook, because I associate my phone with having done so. I want to say that her method of travel involved either a mixture of science and magic or one of those cases of sufficiently advanced technology or magic being indistinguishable from the other. One of the manipulations she engaged in was trying to ruin a particular company to ensure they didn't build a factory on the land where she buried the item valuable in the future.