Hello, Viktor.
Please consider the following notes which enable sorting by dates in reporting framework:
Note 1226594 - The Latest Activities are missing from the Accounts in WEBUI
Note 1598468 - Ascending order sort option in Reporting Framework
First note suggests to maintain table SMOFPARSFA for the key:
Key = CRMRF
Parameter Name = IV_SORT_LAST_N
and to put there the field to sort by along with the component.
Second note describes how to make an ascending sort order option works.
Make sure if you have an implementation of BAdI CRM_BADI_RF_Q1O_SEARCH you should adjust it with the reference to the mentioned parameter.
Also note the limitation from the first note:
The sort will not work in the following scenarios.
1. When STATUS_COMMON field is used in the search criteria.
2. Searching of activities with private flag set for the user.