Exchange Online courses

As far as I know, no new Exchange certifications are in development. Only partly in MS-102 that covers Microsoft 365 more overall.

Third party sites might still have courses online, at least Pluralsight has a few courses. CBTNuggets seems to still have a Certification preparation. But be aware that these courses may not be up to date anymore. You might find some YouTube channels, but I haven't checked myself.

There are still Exchange books being sold but be sure to check the most recent release. At least I know "Pro Exchange Administration" is relatively up to date: https://link.springer.com/book/10.1007/978-1-4842-9591-5. For more PowerShell focus the https://practicalpowershell.com/  books are an option (note: cocreator of those). For more general Microsoft365 focus, I can recommend "Office 365 for IT pros": https://o365itpros.gumroad.com/l/O365IT  which has monthly updates.

Unfortunately, these options are all provided you can self-learn or might miss important real-life nuance and trainer interaction. Of course you could use fora, social media to ask your specific questions. As a last resort you could ask known trainers (MCTs or often MVPs) to develop a custom course or workshop.