Yes, thats a big problem, i'm always stuck. I can't play because i have no energy. I have also updated the gem mine. but after a while you still run out of gems to buy energy. Or you are without XP again. I think this is supposed to that people get stuck and pay for it. even if you pay like me for the gems, to unlock the gem mine total, you still get stuck .
you cannot continue playing the game very annoying.

It's a freemium game. They intentionally hamper you in some ways to encourage spending. Also, this topic is on Platinum's list of items they won't even consider revising at our behest. 

If you don't have enough energy, I suggest doing the following;

1. Use your free gems only for energy

2. Strategically use your energy during events whenever possible to maximize rewards

3. Start a second account

4. Do something else

5. I would say buy the energy packs (some are a really good deal IMO and some are meh) but I've vowed to Plarium to discourage spending until they fix champion AI. So don't resort to spending! 

6 months ago I would have agreed that lack of energy was an issue.  I started a 2nd account because of this.  But now if you do this each day:

4 Clan Boss Runs (30-60 minutes)

Use 36 FW keys (approx 1 hour, maybe more ?)

20 Tag Team Arena battles (???)

39 Class Arena battles 

Use all energy available in dungeons/campaign every day keeping near 0 to refill overnight and when offline...

Someone mentioned above only using gems during events.  That is very smart.  

That is a full time job. lol

can't compete with whales anyway...

I would say same as Trips. Before i was "panic" all the time brooke with energy. I am f2p with all gems (from daily, missions ect..) i save gems to buy and max my gem mine i spend my gems wisely, i gather every "free" energy and from daily and advanced, sometimes when i dont have xp i will make my 20 dungeon runs on "normal" just to save energy for when i real need it. When you are f2p you have to calculate every step. Hope that will help you a little to go in right dirrection. 

Happy Raiding!

i

I have another account, but have the same problem with that account.

I think if they would just remove the use of energy from campain on the first 3 lvls. it would remove alot of stress off of all players. 

unhappy about the energy crises! i don't mind spending money on a game i can play, but to get the items you need to build your character requires energy to do it! i got to play an hour today i need the scrolls but get to play this level for 30 minutes is like...duh now i wait to get to go play maybe two times and wait again. so why spend money on a game you can't even play???

not much incentive to keep playing...sigh

Arena, Tag, FW, CB, hydra, DT.  No energy required  :)

In 2020 energy was a big problem.   Time is a bigger problem for most these days.

Do you buy the monthly gem pack that gives gems daily for 30 days?  if you spend the $10/month it is a great help and imo the only thing worth buying.  Thing is you have to buy them every month.  They are not much use if you wait till you need them