Enterprise-E was never expressly stated to have been "designed to fight the Borg." The only ship that was given that description was the Defiant. The Ent-E was most likely designed with many enemies in mind... like the Jem'Hadar, Cardassians, Romulans, Borg and maybe even the Klingons (given that they were at war with the Federation during the Sovereign's development).
Yes, you're right ish, the sovereign class was designed specifically to and for combat against the borg. Again, the E wasn't specifically built to fight the borg, but its design and class were.
I had always thought until Picard season 3; the the E had been taken out of service due to its damage colliding with the Scimitar. Yeah, they fixed her up but when you have damage on that scale its bound to affect things you can't see. I had thought after a few years of service those issues would pop up until they got too big to fix. Kinda like wrecking a car, you can make it look good again but its likely to have issues the rest of its life. Turns out that her end was NOT Worf's fault. Overall, the E is my favorite as it actually made sense and they got rid of that stupid neck section. I always viewed the neck as a massive weak point after Kahn almost cut the no bloody A, B, C or D Enterprise in half. Not really a fan of the F as it was a silly twin neck design and I HATE the G.
