My sell-side mentor @rlind67 always discouraged 'elbow forecasts'. eg saying something would go down, before strongly rebounding. It confuses clients & looks like hedging your bets. But with the inflation story, it is hard to avoid. In fact, I think there are three phases:

1) Noise. Lots of statistical problems at the moment and big relative price shifts, especially going into/coming out of lockdown. see eg Cavallo (2020) and BoE's monetary policy report. Also cost pressures from social distancing, which affects the level of prices (but not trend)

2) Disinflationary slump (2021). Demand will remain patchy and below 2019 levels. Unemployment will stay high everywhere. This will weigh on underlying inflation, even with relatively flat Phillips curve. But remember inflation was sticky after 2008, which surprised economists.

3) Fiscal dominance. Some investors are jumping ahead to this part, thanks to fears of MMT etc. Seems premature, esp as politicians still reluctant to embrace it (look at recent debate). But seems a reasonable endgame since the deflationary slump (Japanization) isn't sustainable

You can think about these phases in terms of demand/supply. Phase 1, both demand and supply collapse. Inflation messy. Phase 2, supply recovers faster than demand. Phase 3, policy finally boosts demand, ultimately going too far. Esp if LT supply inhibited (deglobalization etc)

Timing of the transition from phase 2 to phase 3 is the most uncertain part of this path. 2021 too early. 2022? 2023? How convincing is @StephanieKelton et al? But premature to worry about sustained inflation right now IMO

PS all the action is on the fiscal side. Powell is about to tell us the Fed wants to "overshoot". But with no new tools, they can only get this overshoot if fiscal policy obliges... Politicians already worrying about to pay for what they have done so far, which isn't helpful..