Why's my icecream jelly like?
Ice cream depends critically on the fat in the dairy to form the structure and mouth feel.   Ice cream mixes there fore are typically fairly high in dairy fat.

You have substituted a comparatively low fat mock cream. which simply does not have the fat necessary to create the body of the ice cream.

In fact, the so-called homemade cream recipe is just thickening milk with gelatin, the thickening agent in... jelly (as they in British English, Jello in the US).  It is no wonder that your product has a jelly like consistency.   Also, gelatin is not stable for keeping its thickening (gelling) power when frozen.

Derobert is also correct in pointing out that switching from a traditional churned ice cream to a hand stirred freezer method will also alter the texture radically, although it is likely to make it grainier and icier without the milk fat to help buffer the formation of ice crystals.

Ice cream is a recipe where you do not want to substitute for the specific dairy called for in this way.  Ice milk recipes do exist, and will perform better.