It’s not that serious.

"The procedure might be difficult to scale. The attacker will need to have Android devices in multiple locations sending messages every hour and calculating the responses. The collection itself can take days or weeks depending on how many fingerprints the attacker wants to collect.

“Not only are the collection and the analysis difficult, but then you have also the problem of sufficiently and appropriately configuring the machine-learning model, which is related to deep learning.”

The concern, says Bitsikas, is that a deep-pocketed organization could exploit the flaw to locate government leaders, activists, CEOs and others who desire to keep their whereabouts private.

TLDR this requires a big infrastructure, planning, and a ML model tailored specifically towards you, which means this only really affects big targets like public figures - who wouldn’t be using SMS in the first place if they value privacy.