I did a stint in a warehouse driving forklifts (which was funny because I had no forklift driving experience and the job required high forklift skills so the first couple of weeks required a steep learning curve and a healthy dose of bluff!). Lots of lifting at weird, awkward angles. After a few days my back was in agony, when I came to my second weekend I could barely move and my back hurt so much I could barely sleep, it was just better by the Monday. By the end of that week I thought I should probably just quit before I broke my body, but I needed the money. The following Monday i was feeling okay, got through the week reasonably well and the week after that I was swinging beer kegs around at awkward angles etc like they were nothing, I'd developed the best core strength of my life in under a month, doing exactly what the official advice tells you never to do, and in that state I was absolutely resilient to all the back issues people talk about. Unfortunately my back went back to normal within about six months of leaving that job, and I often jokingly think about getting a beer keg and spending a few hours a week moving it around in silly, awkward ways. Typical gym workouts focus on keeping the muscles in very safe, stable positions. They grow big and look beautiful and are great at lifting weight in those specific ways, but aren't that great at keeping your body stable and safe in real world situations.
You know what's good for building muscle whether in the gym or working in a warehouse? Protein from eggs! They're also loaded with all sorts of micronutrients which are brilliant for keeping your tissues strong, healthy, and resilient, as well as your immune system etc etc.