You need to look at the number of constraints you have in the schedule. Are all of them necessary? Trace the Finish No Later Than (FNLT) constraint dates in the schedule and see impact on activities.

E.g. ID 271 has a FNLT date of 01-Sep-23 and its predecessor ID 270 also has a FNLT date of 01-Sep-23 but ID 270's predecessor, ID 247 finishes on 21-Nov-23, therefore it has a Total Slack of -304 days because of the FNLT constraint date of 01-Sep-23 on IDs 270 & 271.