The US government issued more stimulus money than needed. When economic output fell by $2.3T, the government spent $3 trillion to prop things up. That excess money leads to excess artificial demand, relative to supply, which leads to price hikes.
Proposed responses, such as California’s gas subsidy, will lead to more demand and higher prices, making things worse.
Source: Blame Insane Government Spending for Inflation
I am so old, I remember early 2021 when expert elites told us inflation would be mild and temporary.