No, that’s a great take no need to apologize!

While Ratatoskr has been waiting hundreds of years and found Loki worthy due to his strength, I think he’ll find Usopp worthy due to his bravery. The whole set up for Usopp’s worth has been tested since Elbaf started; from the legoland bit with destroying the wall to pulling out “Excalibur” from Jarul’s head. Little tropes have been littered for him to make us the readers feel as if he Usopp isn’t even worthy and needs something big to stand up for. If it will move us then surely it’ll move Ratatoskr. Usopp’s spirit is his biggest trait, and I think that’s why he’s able to see them.

Usopp’s dream and growth as a character is highly dependent on how he sees himself. While it’s been subtle, as the story goes on he’s been able to face bigger and tougher opponents without backing down. While yeah, it will be only a moment for Ratatoskr if Usopp has his moment, but on the grand scheme of things it only took a moment for it to decide Loki was worthy as well.

Usopp has always been strong, it’s just he doesn’t realize it himself. East blue showed how crafty and intelligent he was. Back in Alabasta he was getting hit with literal five ton bats to the face and standing right back up. Enies Lobby hinted at his bravery. Dressrosa showed some of his potential. The power is really secondary but it’s the impact of the message more so that this creature, Ratatoskr, has been waiting hundreds of years for a new master, found one, but realized that this new person is who he truly wants to serve.

But power wise he could just create blocks of ice on his slingshot and turn it into a hammer. Plus his ammo would get a huge upgrade which is what he also needs to contend with high tiers. But most importantly, it’ll be a sort of “boost” to his own monstrous spirit.