Rest days are not mandatory, that’s a matter of programming. /r/gzcl was started by a guy who has done more than 1,000 training days in a row.

Orthodox weightlifting has athletic/competitive roots, which invites a certain level of injury, but modern kinesiology and joint-centric lifting create a very different injury profile.

Work with a PT for detailed specifics, but 7 days a week lifting programs for seniors are possible and a decent starting point for decrepit middle-aged IT workers training for longevity.