remove the spark plugs to make turning the engine over easy.
then inspect the crank pulley for time marks.

if no joy...
if you remove the crank bolt you should see the keyway with a mirror.
that will get you close to the time mark, it maybe painted over heavy.

yea total pain to get in there, but a mirror on a stick helps!

and yes on the belt off!
that belt tension setting will make the time move.
check it real close...

and if all else fails back to old school engine setup with reverse dial indicators on both the cam and the crank for tdc.