Give yourself some time to learn the ropes.
Unless an expert mentor is guiding you with every little detail, don't expect to jump before you crawl or walk.
Before you try and throw more changes into your mix, try to stabilize on your sizing techniques, priming technique, and powder charge. When that is stable and your group size is stable, then very carefully try to see if your neck tension causes any variation before you attempt to play the seating depth game.
ETA: eventually, mature brass hardens with pressure cycles. Not sure if you are annealing your necks or not, but expect to feel seating forces change as your brass gets cycles unless you are annealing. Don't take on annealing till you are more experienced and ready for it. It isn't mandatory.
To understand what is meant by stability in the above paragraph, you have to "keep score" over many matches in different weather conditions, and get several cycles under your belt.
It takes attention to detail, a sensitivity to detect problems or inadvertent changes, discipline and experience, before you will be able to even notice if things like seating depth changes make a difference.
If it takes about five or six thousand rounds to train a kid to the level where they start winning matches, it takes a significant part of that time for their loading techniques to get to the level where they have good control over small changes. Even then, if they have been guided there by expert mentors, they are certainly not considered experts at load development or internal ballistics.
In other words, when an expert loader tests the difference between Norma brass and Lapua brass, and the shooting is done by a High Master, we might be able to call a difference due to the brass characteristics. When that test is run by the average bear, it is noise.
My advice: Use the Norma brass you have in your hands now, and learn to inspect and track it while you get experience and the brass accumulates cycles. You will soon run out of something and learn how hard it is to just "keep things the same" without even trying to make changes.
Some folks get a lot of fun out of experimenting. Nothing wrong with getting some Lapua brass, but to answer the question above you don't need to if you don't have the bandwidth to add those logistics.
You can always fall back on side-by-side testing of your best against that factory load as a measure of merit. Once you get the hang of loading/shooting to the level where you are good enough to spot errors and have learned what batch changes can do to your tuning, you will know you are ready to visit with making more changes. Nothing wrong with Norma brass that is filtered for defects and well prepped.
Enjoy the journey. There is something to tying your own flies and loading your own ammo that scratches a different itch than just buying those. But, when there is music playing, it is time to dance and if shooting factory ammo or fishing with a store bought fly means jumping into the game or sitting on the porch, I vote for jumping into the game. Carpe Diem!
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