Can you push the flywheel BACK AND FORTH, even a little, with a pry bar?
Was there any event (machine striking something, etc) just before issues arose?
A worn block would allow the flywheel to have the above mentioned play.
For it to
wobble, it's either not seated, the crankshaft bent, etc..
With the flywheel off, clamp a steel coat hanger to the block. Set the end of it
to JUST TOUCHING the end of the crankshaft (smooth surface). Now, from the other end, rotate
the crank looking for "run out" (AKA a bent crankshaft).
.