Maybe it's just too early in the morning for me or I don't know enough about Python, but why would the OPs code snippet keep the list in memory, and why is yours an improvement?
Also, is this something you could handwave because of Python's garbage collection, or is that not going to help in this case?
I daily drive graphene. It's very good and I haven't had any issues with it. I think the security/privacy claims are somewhat overstated but it's definitely better than stock and gives you a lot of freedom in terms of how you mitigate advance of the Google empire.
It depends on your threat model. If I'm trying to avoid Google-controlled hardware or firmware, it's bad. If I simply assume that the software or hardware is compromised, I have no escape from tracking, unlike with hardware kill switches.
Also, is this something you could handwave because of Python's garbage collection, or is that not going to help in this case?