If it's bricked it's not for no reason. You messed around with the internals, even just a fan, that could be it.
>but I was careful
Maybe there was a manufacturing error and the a trace shorted when the fan circuit was energised
>but I wasn't powering the fan from the board
Not trying diagnose a board I've never seen, just making the point it wasn't nothing, like why you reseated the ram just in case.
If you can access the drive without a stream of errors and without having to leave it at a data recovery shop then your drive isn't corrupted. Buying a new motherboard sucks, especially if it's old and you'll need new memory modules to fit the new one, but the data are usually harder to replace.
Put your drive in an enclosure, boot from it on the same or different hardware. Being Windows it might complain about new hardware but at least you're bypassing the onboard controllers in case that's a problem and you know the drives work on different harfware. Or is that what you meant by
>I used external SSD drives to see if my data was still intact
If it boots from USB but not internal drives then that points towards a controller, cable, or power supply issue.
Remove all the ram sticks, power up and wait for the proper error signal. Replace only one. If you have onboard graphics remove the graphics card. See if it boots.
Try booting from your rescue drive. The one you made on a USB drive. You're smart enough to have backed up your drive twice sort of recently so you'll have a couple of those.
Try booting with a non windows OS. A live linux distro is extremely useful for fixing a lot of windows problems. You can make one with an old android phone, EtchDroid, and an OTG connector if you don't have better hardware.
If either of those two boots are successful with all the hardware connected then you've at least eliminated it being a mobo, video card, memory issue.