Hi! Thanks for reaching out to the community! Specifically in regards to the 2,000 number, that is actually a limitation on how many group rules you can have in an org. See the reference for that here: About Group Rules

As for a limitation on Push Groups, I do not see anything that indicates there is an absolutely maximum number. Please see here at Can A Group Push Contain All Okta Groups, where it does specify that the maximum number of groups to be pushed as part of one group push is limited to 100. Although, in this case though it is not clear, I believe they are referencing Group Push by rule and not name, which is not supported by AD anyway. (you can specify groups by name only)

Here you can find a reference that ultimately does answer the original question however, Is there a limit to the number of Push Groups we can add for an app in Okta.

In it, they provide the following, "From Okta perspective, there is no documented limitation on the number of the push groups for an application.

The only limit that may occur here can come from the service provider's side. They might have a limit of how many groups you can have in their app and thus limit the groups that you can push from Okta."

As there is really no limit as to how many security groups can be created in AD, you should be good to push as many groups as needed/desired.

I hope that helps!! Thanks!