It seems I don't understand the point you're trying to make. Do you believe those guys won't be on the Packers roster in 2023? If that's true I vehemently disagree with letting Alexander walk away. The others might be gone but moving on from both starting safeties would be a terrible idea as well.
As a side note, the Packers can negotiate an extension with Gary once the new league year starts keeping his cap number down for the '23 season.
While the cap might increase that much for once at the point the new TV deal kicks in I highly doubt that will happen every single season.
FYI the new deal has already been signed and will definitely result in the salary cap increasing drastically in either 2023 or '24.
The NFL announced Thursday it has signed long-term agreements with media partners Amazon, CBS, ABC/ESPN, FOX and NBC to distribute NFL games across television and digital platforms, along with additional media rights.
www.nfl.com
See above, the salary cap will increase because of the new TV deal already signed.