LAPS Rejected. What now?

A proposal for LAPS was rejected by my manager. I just started my cybersecurity career. Only have offensive certs and helpdesk exp. We have 1000+ machines with same local admin password. Are there any other methods i can use to eliminate or reduce pass the hash attacks? Please, any advice is a life saver

Just to be transparent. Nobody on my team understands things like DC sync, pass the hash or security in general. They do things like set passwords to never expire and use Password1. I have been fighting for training for staff in IT in cyber but bcuz i lack experience my manager disregards me. I have to go to executives one on one to get backing.