IF (note that's IF) the mis-alignment was significantly less than an inch, perhaps just a tenth of an inch, and this could be "corrected" by lifting the drum ....
... and potentially then move it a further tenth of an inch beyond the aligned point (so that's total play/movement of a fifth of an inch)
AND it HAD NOT developed this fault in just 3 days ....
... then I'd have said that your bearings had failed.
Usually it takes time for the bearings to wear out and become very noisy when spinning (not so bad during washing) and play develop such that you can see it if you try move the drum UP & down by hand.
SO, given the short period of time from being quiet and OK, to being very noisy and REALLY BADLY out of shape I think it's THE SPIDER
The SPIDER is like a VERY FLAT TRIPOD mounted (bolted or riveted) to the back of the drum. At its centre is the SPINDLE that goes through the 2 bearings mounted in the Washer TUB and has the drive pulley attached to the end.
These Spiders can be prone to corrosion and ultimately will fracture such that the Drum is no longer "STRAIGHT" or BALANCED and PERFECTLY IN-LINE with the spindle.
Usually these (BEARINGS and SPIDER) can be replaced (professionally) at a cost that is much less than buying a new washing machine.
It is something that a reasonably competent DIYer could do for themselves. That's all I am and I've done it 4 or 5 times in the last 20 years.