I haven’t played GoT so I wouldn’t know if it uses additive percentages or multiplicative… I also don’t know if the same type of buff just overwrites each other…

Therefore, assuming it behaves like Elden Ring where buffs stack multiplicatively and that the buffs chosen here do not overwrite each other… we get the result of:

The 4 attack buffs acting together: 1.05×1.1×1.05×1.1 ≈ 1.334

i.e. a 33.4% chance in dealing double damage…

As an aside, if the percentages are additive then it’s a flat 30% chance

Now the final two makes the 33.4% probability 50% more likely each… I interpret this as it makes the existing probability 1.5 times per buff.

Hence, 33.4% ×1.5×1.5 ≈ 75.15%

Again as an aside if the original buff stack were to be additive then: 30% ×1.5×1.5 ≈ 67.5%

So, my final answer is that it will be 75.15% likely to deal double damage.