It's just you. I usually never giving many hope to NP 1 servants, especially if their skills isn't maxed yet. You can try maxing her skills, bring more support to boost her damage (Koyanskaya, Chen Gong, Shakespeare, Paul Bunyan, Bartholomew Roberts, etc), and use more offensive CE on her, like Aerial Drive, Black Grail, etc. If you're still not satisfied, then the only way is to get more copies of her through gacha, which I didn't really recommended when she didn't get her rate up banner.

Higher level skills matter a lot more than you’d expect. An Artoria with level 10 skills as opposed to level 5 is gonna do a ton more damage, and especially being supported by a Koyanskaya with higher level skills will make all the difference. As others have said, a CE that also provides damage as opposed to kaleidoscope which just provides np charge will also help. 

You solely can't rely on Grails if you want big damage numbers, because the state and damage boost you get from 90-100 is a very small increment. If you have mats, try to raise skills to at least 6/6/6, especially Koyanskaya's. She is one of the best Buster supports in the game rn, and you're missing so much damage potential by keeping her skill at such low levels. And if don't have necessary skill materials, wait for an event or better get to grinding

As mentioned, it takes more than some grails. NP levels are important, skill levels are important, support skill levels are important, CEs are important, it all works together.

As I don't own Artoria (Saber) for examples, here is my Demon King Nonunaga during a recent event that boosted her damage further. L100, 10/10/10 for skills, 10/10/10 for all three supporters skill, a strong CE. The only difference between the two was an extra NP level. And that still makes a lot of difference between the two.

Here is NP2

And here is NP3

Pretty big difference there. This isn't a case where Nobunaga is super powerful and Artoria isn't, it is the work put into getting there that makes the difference. That takes time. As you play, you will farm materials to boost her skills along with that of her supports. Eventually, she can blast an enemy away with a overwhelming attack. But not today.

I'd also add that you haven't even upgraded her NP through rank up, that too makes a world of difference.

Don’t grail a servant unless you really want to. If you’re trailing for gameplay wise you won’t be as satisfied as grailing a favorite. I agree with everyone here. Either invest 100% into your King or just expect that she’s not gonna satisfy you. Don’t be discouraged though. There are times I’ve used my Proto King and wished he’d done more damage but it it’s all about investing. Also it seems that you didn’t knew how the power scaling works so maybe do some research on a servant before investing.

I respectfully disagree with that. It always comes down to gameplay when grailing servants, because grail just raise more attack and HP from the servants above their usual limit. Besides, people want their favorite servants to be stronger, and grailing them is one way to do that 😅

My NP2 saber can clear the extreme difficulty rider daily quest with double koyanskaya. Remember to raise all their skill levels and clear the rank up quests. It just shows how strong she is when I can use her for rider enemies (3rd append skill unlocked for the damage)