You could update Exchange to the CU 23 directly.
My question is do I need to perform any additional steps inoreder to upgrade exchange mailbox severs & exchange edge servers to CU23 as we have o365 Hybrid configurations?
is it going to remove all connectors on exchange edge server if I upgrade to CU23? please also share how to change edge certificate as we copied our on-prem mailbox server certificate to exchange edge server and currently edge sync is not working.
You don't need to copy any certificate. Exchange Edge use a self-signed certificate. You could follow this article to remove Edge Subscriptions and create a new one.
Do I need to re-run Hybrid configuration wizard on primary exchange server 2016(mailbox server) after CU upgrade?
It is suggested, but not needed.
Do I need to backup exchangetransport config files before upgrading? Also, our exchange delegation federation certificate is expired please advise how to renew it as it is self-sign certificate.
You could backup this file. About delegation federation certificate, here is detailed information about it: Renew the federation certificate
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