If we'll figure this out, we'll (very) probably also have figured how out to calculate the effects of communicating with the past.

So, no. This doesn't tell us anything about the possibility, it merily tells us, even if it _was_ possible, we're collectively to stupid yet to deal with it without destroying our future which would've led to inventing such a device.

The physics of interacting with your previous self are undefined with many plausible solutions.

It is entirely plausible that the universe limits your interactions with your past causal self to a small range, allows arbitrary overlapping world lines, blocks all causal violations entirely, or has disastrous consequences for time loops.

My personal bet is that the universe has no reason to care that you've interacted with your past self given a consistent proper time worldline. This however removes conservation of energy and momentum in the universe, which General Relativity also does not preserve.

Of course this does allow for misuse of causal loops to generate arbitrarily large/infinite amounts of energy without any bounds on observability.

In the abstract of the linked paper in the article, they mention that wormholes "can't violate causality" [1]. So, this wouldn't be possible even if we were able to invent wormholes in our lifetime.

[1]: https://link.springer.com/article/10.1007/JHEP12(2017)151

It could be you can only communicate back to the point where it was built.

unrelated tangent but this reminded me a funny thing i read

inspirational quote: "Your future self is complaining about how much time you waste"

person: i'll show him! i'll ruin his f**ing life!