Influenza is a virus in the Orthomyxoviruses family. It's a negative-sense single-stranded RNA virus in the Negarnaviricota phylum. It looks like this:
SARS-CoV-2 is the virus which causes the COVID-19 disease. It's a positive-sense single-stranded RNA virus in the Pisuviricota phylum and the Coronaviridae (hence: coronavirus) family. It looks like this:
Other differences include the rate of spread between humans (R0). For Influenza, the typical R0 is 1.3-1.6. For SARS-CoV-2, the R0 is estimated at 3.28. The infection fatality rate for seasonal flu is about 0.1% For SARS-CoV-2, it's estimated by the CDC to have a lower bound of 0.26% and Johns Hopkins puts the likely IFR between 0.5% and 1%, which would make it 5-10 times deadlier. Seasonal flu causes an average of about 37,000 deaths in a year in the US (https://www.cdc.gov/flu/about/burden/index.html. SARS-CoV-2 has killed 136,461 with nearly all of those in the past 4 months. That's about 3.6 years worth of flu deaths in 4 months. And that number is currently accelerating upwards in the US.
It's certainly valid to have an opinion that the severity of the SARS-CoV-2 virus does not warrant such a reaction as we've seen in the US and other parts of the world, but it's also a fact that Influenza viruses are completely different from SARS-CoV-2, both in terms of their structure and genetic code, as well as their impact to humans.