iMac crashes

Hi guys, In the last 4 months, my iMac has started to freeze spontaneously. The activities I perform are office tasks, electrical circuit simulation, machine virtualization and casual gaming through Parallels Desktop. I constantly have many windows, tabs open in Safari and Chrome and PDFs. I also have an external hard drive connected via USB that runs 24 hours a day, a Lightning to USB cable to connect devices and a USB to USB Type-C cable. I usually only put the computer to sleep when I'm not using it.

The times my iMac has crashed have been when I'm working on a report for a class, with 30 tabs open, Parallels Desktop with Windows 10 and the external hard drive connected. I tried disconnecting the external hard drive and reducing the number of tabs and windows open, as well as turning off the virtual machine, however the problem persisted and there have been times when the top menu bar on the screen turns red.

My computer's specifications are: Retina 5K, 27-inch, 2020, Intel Core i9 101910 10-core 3.6 GHz, 1TB SSD, macOS Sonoma (14.2.1), AMD Radeon Pro 5500XT 8GB and 128GB 2666 MHz RAM. In the case of the RAM, it was purchased through Other World Computing (OWC) and the first time it had a serious RAM error, so I had to request a RAM replacement. In early 2023 it was working fine with the replaced RAM, but in late 2023 it started to show these anomalies.

I would greatly appreciate your support and recommendations on what I can do to prevent the computer from freezing.