Some criminal is trying to sell new old stock AAVID fans over at a german voodoo forum (voodooalert) .
For a single fan he's asking exactly the same price that you payed for the whole card (25€), so it's probably not a reasonable proposition...😁

I just looked it up again. That offer does include the original heat sink as well.

the fan connector on the voodoo is JST PH and is not uncommon at all 😉 you can just crimp the connector yourself.

the connectors of the fans you posted are different, the top one looks like JST XH and the bottom one like Molex PicoBlade

there are fans being sold with JST PH connectors if you don't have access to a crimping tool, you just need to check the pinout.

The new AAVID part number for a replacement heatsink-fan combo is 11-5602-47. Sadly as far as I can tell they're only avaliable from said scalper or as a 1000 piece order from the manufacturer.
Mouser sells a compatible heatsink with fan from AAVID for 7.02€ per piece. Mouser-Nr. 532-11-5602-46. That's the AAVID 11-5602-46.
It's almost the same part as the original with the 3 pin connector and 5V operation. It also has convenient tabs and push pins for mounting (thermal paste instead of thermal compound glue😁👍) but the fan only has one ball bearing instead of the two ball bearing on the original. You can however get a replacement two ball bearing in many hobby craft stores for pennies and swap it.

I believe this is the best readily avaliable and almost original looking replacement right now.

Thank you all for your suggestions, I'm very happy to see there is many choices!
I managed to test the card, and apparently it isn't completely dead!! 😁 I got a small heatsink and I put just a little bit of thermal paste and kept my finger so it wouldn't fall.
It manages to boot into the OS in 4-bit mode with some artifacts apparently... This is the only picture I took: https://imgur.com/a/udKQjv9
Trying to switch the mode to 16 or 32-bit makes the system hang. Also there are these little Artifact dots in a Horizontal line.
I tried to push just a little bit with my two fingers into the heatsink, so I could create some pressure into the chip, and see if the Artifacts would change or go away, but nothing happened. I suspect the culprit might be one of the Ram chips, which if it is the case I'm super happy!

@Der Kuenringer,
Thank you! While searching on Google, I think I came across this guy that is selling them, but I didn't understand much because it was in German.
I wouldn't go as far and call him a criminal 😜, I mean he is selling an original Fan with Heatsink included for 25 euros. It would cost me 8-9 euro for a Chinese fan that I'm not sure it is compatible, plus the cost of the heatsink (which I can manage to find one since I always keep many as spare), plus the cost of the Pin Header... So in the end it I would pay between 13-14 euro for something I don't know if it is compatible or that could also damage the card. Personally it would've been the solution I would go if the card was fully working.

@imi
Thank you for your information about the Pin Headers. That way I can find cheap 3Pin Fan locally and only buy and change the Header!

@Doornkaat
Thank you for letting me know that they're selling NOS AAVID fans on Mouser, I already need to order something from them, maybe combining the shipping would make it a reasonable purchase. I noticed that the 532-11-5602-46 is a 28x28mm fan, but the one that goes into the V4 should be 40x40mm, am I right?
A quick search on Mouser gives me other options for AAVID fans, which is super cool, but they all come with a heatsink with two pushpins that I cannot mount into the V4 holes, since the holes are too small and the position is different. I need to search better.

Thank you all for your suggestions, the help and information I got went way above my expectations!
Since the card is not fully working I'm taking my time with finding a compatible fan and heatsink. Cheers!

I think there's a discrepancy between Mouser and the AAVID datasheet.
Mouser indeed lists the part as 6x28x28mm. The datasheet lists the whole assembly as 40x40x15mm. Better ask Mouser what you're going to receive if you consider ordering. 😅

@Doornkaat,
that Datasheet link was a sweet touch, thank you!!!