"Toy" cameras like these can produce great work and are fun to use and can teach you a bunch about film. Given the lack of exposure adjustments one of the first lessons will be how to pick the right film for your uses.
Personally I go for fast (400) to really fast (800+) negative films. These films, color or B&W, are very tolerant of exposure variances. Conversely, transparency films like the E100G you are playing with, like very precise exposures and that's not a really a toy camera's strong point.
As for the hope of comparing typical 120 film results to typical 35mm results by using the Debonair, um, that's about as scientific as trying to compare strawberries to steak to decide which tastes best.
The reality is that they can both taste good or bad, just not the same.
A TLR like you are looking for will provide a better comparison of the capabilities of 120 and 135 film in a technical sense.
Still and yet, IMO that's a poor way to pick a tool.
Every camera I own helps me look at and portray the world a bit differently than the others.