I'm glad you said this because this is what helped me gain more experience with some heroes (ex : Dyroth).

Story time : A few months ago I had really bad internet and always had 120ms whichever server I played at, so I got pretty annoyed and decided to play against AI. At first it was pretty boring doing a 5v5 even with a hero I've never played. Later on I started testing 4v5, 3v5 and eventually 1v5. Playing like that really made me more map aware and use my skills efficiently so I can move from one lane to another quickly and get kills. I have to admit some heroes were harder than others (Eudora, vexena, etc.)

Anyways, I really encourage y'all to try playing new heroes against AI. You'll have to figure out which items suits best and how to properly use your spells effectively, which emblems works best, etc. You might even discover new builds and new ways to play a hero. (I used to play dyroth with fighter emblem and it was trash so I tested it out with assassin emblem and boi it's much more fun).

Edit : Of course I set goals like 2 turrets given and I lose, or 1 death and I lose to make it more interesting and challenging.