My opinion is the best strength training routine is the one you can stick to. Sometimes you get into a routine because someone told you it's the way to do things. You try to force yourself to do it even though you don't like it. Eventually you stop doing it because you're not motivated to do something you don't like. At that point you might think, "if this is the way I'm 'supposed to' workout, but I don't like it, then I've failed and just won't workout because anything else is not the way you're 'supposed to' do it". Don't listen to anyone who says you have to do one thing or another. Do what you like because you'll be more motivated and stick to it.

This has been my experience... Personally, I don't like going to a gym. I'm not a fan of the atmosphere. I've tried several gym-based workout routines and I just never enjoyed doing them. When I say gym-based, I mean routines that really require gym equipment and access to heavier weights.

I also don't like workouts that waste a lot of time. I found with gym-based workouts I always had to keep looking up each exercise because I would forget exactly how to do them and that wasted a lot of time. There also seemed to be a greater risk of injuring yourself doing certain exercises, especially those requiring heavier weight. I also found exercise routines advertised as being "simple" or "basic" would have several exercises requiring equipment my gym didn't have, so I always had to figure out alternative exercises for that muscle group, which also wasted time.

I ended up doing P90X for a few years, which was great for someone like me that always has other things occupying my mind because I didn't have to think about what exercises to do. It was all laid out for me. Also, I could do it at home and it incorporates HIIT, which allows you to get in some cardio. As I got older, I found P90X felt like it was over-training and I couldn't keep up with the intense hour-long exercises. I switched to P90X3, which has 30-minute routines. That was good for a while, but personally not enough strength training for me. It had a variety of exercises (because variety is kind of the P90 way), but a lot of the exercises didn't really feel like they required enough exertion. P90X3 is probably good for someone starting out though if you need to get a basic level of physical fitness before moving on to more intense stuff.

After P90X3, I purchased RIPT90 Fit, which is very similar to P90X3 (30-minute home workouts) but is cheaper and has fewer, simpler, and more impactful exercises that I think maximize your 30-minutes. I still occasionally mix in some P90X3 routines, like yoga and core workouts.

HTH