Further reading that explores various levels of intervention across 16 US Cities and their affects on total cases for 1918 Spanish Flu: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1849868/
Fig 2, chart b is a good thing to look at. The red line indicates our current trajectory if we stay under restrictions for a short term and then open them up (such as schools opening, concert venues and stadiums opening, etc). You have to account for the differences between COVID-19 and the Spanish Flu, but the general shape would remain the same... spike now, another spike later. The second wave of Spanish Flu hit hardest due to a mutation and its disproportionate affect on younger, otherwise healthy people. Whether or not COVID-19 will mutate in any fashion (we hope it will mutate to a weaker strain) is a big 'ole TBD.