It's interesting that you say this, do you have a source to back it up? Everything I've seen says that the fatality/infection rate was about 2% for Spanish Flu [1] where the official numbers for Covid-19 are around 3%[2] . Naturally, since this is still "in flight" the numbers will change, but I've not seen anything that suggests Spanish Flu was "much more dangerous".
[1]https://www.biospace.com/article/compare-1918-spanish-influenza-pandemic-versus-covid-19/
[2] https://coronavirus.jhu.edu/map.html
So you don't think a virus which kills a lot of younger people is more dangerous than one which mostly kills people who have already reached somewhere around the average life expectancy?