I wouldn't exactly call a comparison between gene therapy "isn't quite the same".
Flu shots contain inactivated/weakened flu virus (depending on the version), to the presence of which/antigens the body reacts by creating antibodies.
RNA vaccines are a different technology, which transfect (reprogram in IT speak) your own cells to produce spike proteins similar to the ones sars-cov-2 does (the consensus seems to be that this spike variant is, unlike the real one, harmless and is not free floating) which are then detected by the the body and antibodies are created.
The result is esentially the same, but the way you get there contains an extra step and it is this extra step that is the source of the vast majority of (rare) adverse reactions. Blood clots etc.
The ironic thing is that most people who are very strongly opinionated on this (both sides) have no idea what the actual difference is and blindly trust whatever either the government or a local anti-vax facebook group tells them.