Inflation is really one of these things where people find out much later that the problem is fixed. For instance, Biden inherited a high inflation regime which baked in about 10-15 percent price increases before he could do anything to stop it. By the time he brought inflation down, prices had increased by something like 20 percent. Inflation has now been brought down to 2-3 percent, but most people will simply observe that prices are 20 percent higher than when he started.
Another big issue is counterfactual reasoning. US inflation was lower than in other developed countries, but people only notice that it was higher than they were used to.
In a nutshell, policy is really complicated. You do not feel the consequences of good policy in your bones.
As you rightfully note the relationship between federal economic policy and economic outcomes is complex and it’s not easy to tease apart cause and effect. Having said that Democrats have through history presided over MUCH better economic outcomes than Republicans, and Biden is no exception. Yet, voters consistently believe that (generic) Republicans are better for the economy than generic Democrats.