The idea of velocity is pretty simple. If you print a $1T coin and hand it to me, then I throw it in a safe and forget the code, did the increase in supply cause any material increase in inflation experienced at the point of sale by the average person? Probably not. The supply went up, but the average velocity went down commensurately.

How this interacts with assets is in my opinion not super clear. Pricing of assets is supply and demand, unlike the CPI basket. The CPI basket is based on human need. There's no human need for AAPL shares. However, there's a ton of stimulus money, and folks who remember 2008's V-shaped recovery, and a bunch of people stuck at home day trading. I think that's much more likely to be driving asset prices than supply. After all supply is enacted by changing lending parameters.

To the extent asset prices don't put pressure on CPI, they reflect an increase in welfare, not an increase in inflation.