Leveling and XP gain

What’s the deal with leveling characters? Ive played a total of 60-100+ rounds of hoard total (May be off) and ive gotten Jack to the grand old level of 5. How? Why? The difficulty is as high as i can make it. Am I missing something important? Frequent dissconects also cause me to gain little to no XP for the character im playing as. Yet one round of Escape got Kat to level 4. Just one round!! Any clarification of what is going on is welcome! Pardon any spelling/ grammar mistakes, typing on mobile

There is some really weird xp curve. 20 rounds to reach lvl 3 + and then nothing.

Yeah, its kinda dumb. Considering theres already nothing worth grinding for, the last thing they need to do is take the sense of victory out. (Edit: not skins worth getting and no challenges for jack. Cards are still worth getting)