Your scenario is more like a best-case option, actually. I mean currently there are only 13M people employed in manufacturing in the US [0], while output is at an all time high [1]. The vast majority of this manufacturing is dependent on components imported from other countries - which just got much more expensive. So even if employment in manufacuturing would increase by 20% (unrealistic IMO), that would only translate to 2.6M people - while at the same time losing multiples of that in better-paid jobs in other industries, mostly services.
I think you might even lose a bunch of these jobs, at least in the short term, as businesses now need to free up money (they likely hadn't planned to initially) to pay for tariffs before their goods / parts are auctioned off at the port. That's even before consumer spending tightens up due to rising prices, and declining stocks.
[0] https://fred.stlouisfed.org/series/manemp [1] https://www.macrotrends.net/global-metrics/countries/USA/uni...