Welcome to the forum Isaac. Great to have you here!
My advice is to sleep on it. Practicing before you go to bed (when possible) is a neat trick that works for a lot of people. There's some science behind it. Here's a link: https://lifehacker.com/5896513/study-before-bed-for-significantly-better-retention
Of course, this alone won't solve all of your problems. Your expectations may be too high as to how quickly you should be able to master beats and solos — simple or not. It's not uncommon to spend an entire practice session on something only to end the session without having been able to play it yet. It's a frustrating experience, but getting back to the 'sleep on it' recommendation, new things take time for your body and brain to learn. You'll often recognize that on the following day, you're able to progress a little further during the practice session. Then, of course, the day after that you get even further.
It's a long cycle at first, but as your skills develop, new things begin to come easier. And the great thing is, once you've put in the time to learn those skills, it's like riding a bike — you never forget them.
Does anyone else have anything to add?
Keep us updated as to your progress, Isaac. Keep drumming!