A Race cancelled how do I make the most of the ANR/VO2 fitness?

So I targeted 2 A races this season one an XC race in June that was cancelled due them not being able to get the course ready in time following last fall’s hurricane. Now my other A race, a road race this weekend is cancelled because of the coming hurricane. There are 4 or 5 weekends of CX races and a few other fun road ride events but thats pretty much it for my season. I’ve heard before that VO2 work raises the roof and then you have to put hay in the barn kind of thing to turn it into FTP gains.
How can I best do that given I have a few more events coming but nothing I would try to peak for?

I use my fitness on Strava segments or long climbs.

I guess I don’t mean what should I do but rather how to best turn it into a long term fitness gain.

20min max test