1. You can create up to 50 criteria-based sharing rules per object.

2. Text and Text Area fields are case-sensitive. For example, a criteria-based sharing rule that specifies “Manager” in a text field doesn’t share records that have “manager” in the field. To create a rule with several common cases of a word, enter each value separated by a comma.

Check the below links for more information

https://developer.salesforce.com/docs/atlas.en-us.securityImplGuide.meta/securityImplGuide/security_sharing_cbs_about.htm

https://help.salesforce.com/articleView?id=overview_limits_general.htm

To increase sharing rules limit, check

https://help.salesforce.com/articleView?id=000231052&type=1