Themken: I hear Romanian deadlift has caused damage to quite a few as most are not flexible enough. Maybe have someone check you while doing minimal or no weight to ensure you really can bend your back enough.
Yes, it does requires some amounts of "refined" muscles and flexibillity to do it, as some exercises dos, especially concerning the back. I've seen some that progress way too far too fast and have gotten back pains from it. As a beginner it's best to refrain from some of them before the core muscles are ready for it. Even the spine doesn't like it either unless you have the muscles for it.
Same goes for doing full situps without having a strong back. When I did TaeKwon-Do we first learned about this and never to lift our lower part of the back until the body could fully handle it.
Actually, the best thing is to start the first weeks with just your bodyweight and some rope.
I have an old injury in my back from a car accident that I often get some pain from if it goes too long in between my workouts, and I've been too lazy to do anything properly. Due to this casual virus, I haven't worked much on my body for about 1.5 year, if anything at all. Going to the gym did make me have a steady routine each week so I'm hoping to get into it again.
Since I'm pretty "weak" I have to remind myself to not do some of these harder back exercises at least until my core strength is back. I do however go a bit harder on arms and legs alone. Personally, I like to mix things up as it tends to get stale and boring (that's usually what's happening to the body if one stay with the same routine over and over again yet see no benefit from it).
I started up recently myself, and I usually warms up with "circle jerking / bootcamping"; 3-5 different things, 20-30 sec as fast as I can, not much pause in between, and 4 sets/rounds, just to get my heartrate up. Then I proceed to do the usuall 6-8 reps and 4 sets with a good amount of pause in between. After that I stretch out, and sometimes finish with some short semifast walk and focus on my breathing.