Currently facing a situation where a square-ish glass bowl is stuck in a cylindrical bowl in a weird angle. Tried the ice in the inner one and immersing the outer one in hot water but it still wouldn’t budge. Any help would be appreciated.
I can only make a suggestion.
You need more ice in the inner bowl, so it fills it. The outer bowl should be standing in a bucket of hot water, at the same time. Prop it so that the ice in the inner bowl is level, to its brim. The space between them should have no water or ice.
You could also drip some oil around the corners of the inner square bowl to provide lubrication.
Then, stay on the case as the outer bowl expands and the inner bowl contracts (hopefully). It may need some help at the right moment, such as under the highest corner of the trapped square bowl, which isn't level.
Perhaps you can contrive some kind of lever that goes through the gap between the square inner bowl and curved outer bowl, that tries to gently pry up the highest corner from underneath. For example, a metal fork or spoon: or a pair of such implements, one helping the other.
Turn the two pieces over so that the stuck piece can fall out.
Put a small folded dish towel under the small stuck piece to cushion it when it drops out.
Lift the edge of the cylinder a bit and let the cylinder edge drop to 'jar' the stuck piece loose as it hits the counter top.
(Let the weight of the stuck piece help to dislodge it.)
Experiment with lifting different places around the edge of the cylinder and different 'drop' distance to the counter.
Gravity always wins.
At the very least, DON'T store the jars upright which increases the problem.
Disclaimer: this method is a bit more aggressive, so damage (breaking) might occur !
Put the entire thing in the freezer (-18 C), without anything inside or outside for a few hours - to get the inner thingie as small as possible. Take it out, and place the outer bowl in water (room temperature). The outer bowl should grow in size, while the inner "remains" small.
If nothing happens in one to two min, start heating the water - slowly. The outer bowl will expand at a higher rate, releasing the inner one.
Maybe spraying some WD-40 would help - but it might help crack the glass in combination with extreme temperatures.