Reselling: Mint vs Sealed

i had the impression it was backwards! Figuarts didnt go for much more if they were sealed than if they were opened

Sealed, unopened toys commonly will always go for a bit more but it can depend on the figure. However, a complete figure with packaging can regularly command a higher price than one without.

If you do open the figure and intend to sell it later, I recommend keeping everything. Including the little things like the outer brown box, instructions, etc. you can get a higher price for a complete figure with all accessories and with the box. Also pay attention to joints and don't overly stress the figure, some collectors will be picky about loose joints. When I sold my open Hot Toys, Sideshow, Medicom and G.I. Joe figures long ago, I mentioned every flaw each figure had so the buyer knew exactly what they were getting.

You may get differing opinions but I believe they are completely different.

Once an item is opened, it becomes "used" and is no longer "unopened, factory-sealed, brand new, etc." whatever you want to call it.  For example, once you buy a new car and drive it off the dealer's lot, its value instantly decreases because it then becomes a used car. Even if you turn around and try to trade it in the next day, you won't get as much as you paid for it.

Same applies to toy collecting, an opened, near mint figure still has "use" and "mileage" to it. I don't know what you've done to it, if there's paint/plastic damage, loose joints, missing parts, sun damage, smoke smell from a smokey house, etc. A collector will be interested in the history of a toy but will still see it as used and that shrinks the value of it on the aftermarket.

Take a look at eBay and compare the rates of new, unopened figures to opened, near mint ones. Sometimes the price gaps are marginal, while for others, the difference can be hundreds of dollars.

For example. Just saw on eBay that an opened, but mint and complete Figuarts SSJ Vegeta with the box went for $277. The same figure, brand new and unopened this time, went for $387. A little over a hundred difference.

It all depends on other elements too like what the rarity of the figure is, the aftermarket demand and even your own personal decisions (save to sell or open to enjoy and sell later for whatever I can get). I sold figures long ago that I barely got what I paid for and now they go for $400+.   I couldn't get a lump of coal for it and now people want them like crazy!

i sold a loose super saiyan vegeta no box or clamshell with some scuffs for 180$ when new they were selling for 210. If he was mint i believe it wouldve been sold for almost the same price.

Yep exactly you can never know.