It seems that the doctors are confident in the seizure diagnosis despite the tests coming back normal so I do hope they're spot on. It's difficult when the tests aren't telling them everything they need to know.
I will say as far as medications go, totally keep doing the journaling that you have been. Many people apparently don't handle Keppra well (Keppra rage is one of the many reasons - some people get incredibly aggressive and feel angry). I handle Keppra well for the most part (it does keep me seizure free for years at a time with proper dosage and such) and I've always been taking the generics, which still work. When I first started Keppra, I was super tired. Felt like I had been hiking up a mountain with a backpack full of bricks type tired. I was this way for about a week...sleeping most of the time. Thankfully I was 19 and I'm pretty sure I wasn't taking any college classes that semester. If you have to revolve around work or school or anything, figure out a time where someone can supervise you if at all possible or so you can handle any side effects while not having to be somewhere where you need all of your focus. The tiredness subsided 90%, but I still feel tired basically all the time when I'm taking Keppra, I am able to get past it most days.
Doctors a lot of time may prescribe folic acid with Keppra because it takes your folic acid from your body, this is even more so with women that are of child bearing age. I end up buying my own bioavailable folate to take since it's not synthetic like the folic acid they would dispense in the pharmacy. Not to mention, the pharmacists would usually freak out at the dose I was given and then the neurologist would get upset because it's due to the medication and I told that to the pharmacists and they were still awfully concerned so it creeped me out. I do well with the folate I buy and it's not as expensive as other supplements out there.
Keppra for a lot of neurologists I have seen say it's one of the most mild compared to the other AED's if someone can tolerate it. One neurologist said they liked it because it is easily administered via IV if needed and I have been able to take it during two pregnancies, but it concerns me that the pregnancies plus the Keppra drained my nutrition stores because my kids both had many problems with their baby teeth and that alone is so heartbreaking to me (they are healthy otherwise).....I always blame myself when they're scared and in a bit of pain due to the dentist...
Without being pregnant, I find that it's important to take a whole lot of veggies (usually steamed or juiced works best for me, I don't seem to digest raw veggies that well), and helped me feel more on top of it all so lots of nutrition helps. I was recently switched to the extended release, but I've been a lot less fatigued at night so it's possible I was having seizures then. I've got an EEG tomorrow (ugh...) so maybe it'll be able to see how far back COVID set me as far as my epilepsy is concerned.
I hope that Keppra will work for you and keep you seizure free so that way you can get back to what you would like to be doing in life. Medications are a most definite pain, but when it's considering that you won't be having seizures and hopefully don't have to be in fear of having one, that part is a lot better. I'm glad that things are looking up for you!