It’s not hard to verify before throwing shade at OP’s work. 1) article specifically mentions the actual frequencies used by wireless charging up top, 2) you can refer to Wikipedia to see the same [0]: the frequency for charging is the much lower From 87-205 KILOhertz (while the harmful frequencies being filtered out are in the hundreds of MEGAhertz).

So, no, this doesn’t slow down charging.

[0]: https://en.wikipedia.org/wiki/Inductive_charging