It looks like if they allow a 23m fall next year the cap would still go up the following year relative to where it is now due to all the extra income that was expected (assuming things are back to normal by then). Paying it back is not too difficult when the NFL knows the cap explosion that was slated to happen, and likely still will happen. If anything this deal helps them out by evening out the growth and avoiding 10-15% jumps early this decade (yearly for the next 3-4 years) and then dropping to 6% after.
It really all depends on the TV contract negotiations. They're expiring in 2022, so if the NFL can renew before then, it's likely 2021 would go up.
But if the NFL experiences like a $40-50M shortfall this year, which is expected, a $23M drop won't cover all of that, which means they'll need to spread out the rest. So yes, 2022 would likely be at least at or slightly above the current number. It could be substantially higher if they get TV contract renewals by that point.
It'll be an interesting negotiation for sure. One would expect that NFL TV ratings will rise significantly this year, as all those fans who won't be attending games live will switch to watching on TV. Then it just becomes a question of how the TV networks factor that into revised negotiations. 2020 could be an explosive TV number, but is that sustainable? Likely not.