I need assistance with two tasks on my 2011 iMac running High Sierra: 1. **Admin Access**: I lost admin access and need help creating a new admin account. 2. **Software Upgrade**: I'm interested in upgrading to the latest stable macOS version compatible with my machine... (Budget: $15 - $25 USD, Jobs: C++ Programming, Computer Repair, Data Backup, Mac OS, Software Architecture, System Administration, Technical Support, Windows Desktop)