You (probably) don't need to use -A to use a jump box. SSH agent forwarding with -A is unsafe on shared jump boxes where either 1) anybody else has root on the jump box or 2) everybody uses a shared account on the shared jump box, because the connection to your agent can be hijacked and used to authenticate as "you" elsewhere.

Look at ssh's -W or -J options (depending on how old your ssh client is), or see e.g. [0].

[0] https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Proxies_and_J...