I don't think that's entirely the point of the Fermi Paradox;
Kurzgesagt has an awesome youtube video on this link here and the follow-up video here
Either way; to answer your question is a tricky thing to do (see the Wow! signal)
What is an Electromagnetic (EM) signal? Radio waves such as those we've sent out to Search for Extra-Terrestrial Intelligence (SETI) are simply light waves traveling at a specified frequency, but so much can imitate or manipulate this frequency; here are just a few:
We first have to take into account Cosmic Microwave Background Radiation (CMB Radiation) that could distort what is heard.
Next, we have Black Holes. These super-dense remnants of very large stars (>5 solar masses) will warp Space and Time to such an extent that Scientists had to develop a new theory about them in the movie Interstellar.
Thirdly, we have Pulsars, although they won't affect any preexisting radio communication, they will add their own as they spin, emitting light in pulses (hence their names)
Next, as you originally posted, the host star also emits its own radiation that could (possibly) interfere with the signal, though it should be mentioned that when we humans search for EM signals, we search for a specific frequency that, we think, would be used to avoid this kind of interference.
As any EM signal is simply a light wave, it has the same (or similar) properties in terms of decay, that is to say, if uninhibited, it will continue to propagate outwards in the direction it is fired in until such a point that the light wave becomes so long as to become in-discernible against the CMB. (Currently the most distant object seen so far with telescopes is UDFj-39546284, an early forming galaxy at over 13.2 billion light years away)
The point of the Fermi Paradox is to ask "If there's this many stars in the known universe, where are all the aliens?" it's NOT asking "Are we alone in the universe?" because that's not a paradox.
(TBH, the Fermi Paradox isn't really a true paradox anyway and wasn't even made by anyone named Fermi)
Considering all this information, it's not out of the realms of impossibility that a sufficiently advanced civilization (one that can use telescopes to see other worlds and has radio communication) could potentially send a signal that would reach us here on Earth.
The only problem is, Space is BIG, very big. Even in our fastest ships (Voyager 1 and 2), it would still take 18,000 years to get to our NEAREST stellar companion, Proxima Centauri, (At approximately 4.2 LIGHT YEARS away)