You don’t understand the nature of RNG.
Suppose R4 monster materials have a drop rate of 5% in the Basic Rewards per slot, based on the material drop rate survey. This rate is pretty much consistent from 4-star monsters onwards.
Across 10,000 hunts, counting just Basic Rewards, there would be 40,000 Basic Rewards, and 5% of them ought to be an R4, which translates to 2000 pieces. 2000 R4s in 10,000 hunts. Roughly 20% of those hunts ought to see 1 R4. Keep this in mind.
Now, you should have seen hunt reports showing ridiculously good drops, such as multiple R4s.
Suppose that there were 500 hunts in which players got 2 R4s. 2x 500 = 1000 R4s.
The 5% rate is a constant. If 500 of those 10k hunts already had 1000 R4s, then the remaining 1000 R4s will be “shared” across the remaining 10k - 500 = 9500 hunts.
This would make it look like it’s a mere 1000/9500 ~= 10.52% chance for the remaining hunts to get an R4.
Now, you have only hunted how many 4-star monsters?
I didn’t get a clear picture from you, and I doubt you recorded all your hunts, so let’s say that you hunted 500 of them.
Your contribution to this 10k hunts is only 500. Since you didn’t get any double R4s, then your 500 hunts apparently had not been among the 500 hunts that got the double R4s.
Visualise the 10k hunts as a giant grid of square containers stacked neatly against each other laterally. We have 2000 beans (R4s), and a dispenser simply throws them into the air and allow them to land randomly into the 10k containers on the ground.
Your 500 containers are amongst the 10k containers, laid out randomly (chronologically, rather, since there are so many hunts going on at any one time). Do you think all the beans will land in your container?
Your 500 hunts are merely but a drop in the pond. If this was a raffle game, you only bought 500 tickets, and you’re expecting to win it all in a pool of 10k tickets?
If you truly won it all, then 9500 tickets would not be winners. Are they all gonna also call this game “bugged”, just because they happen to draw the short straw?
RNG is like this. It doesn’t care what you need or don’t need. The drop rates are designed to be just nice for upgrading a 1.1 weapon to 10.5 in 2000 hunts of that one monster, on average.
It doesn’t mean that it will give you the materials you need in the first 500.
The drop rates are pure RNG. It has no logic. It doesn’t give you advantage because you’re a new player.
But if you stop rolling those dice, you stop gaining.
Simple as that.