The doors and drawers are the most expensive part. No point in spending 20K on 3rd party doors, when you can just spend 25K on better quality already assembled cabinets.

Any suggestions for better quality pre assembled?

Scherr’s. Top notch quality RTA. Made in the USA. Excellent customer service.

They also specialize in making doors for IKEA cabs.

We have ikea cabinets (love them). Installed Scherr's doors. Perimeter cabinets are a creamy color (their factory selected cream color), slab door and island is oak, slab doors and drawers. They were recently installed. Many of the creamy white doors are not holding up - definitely not like their sample they sent. Dings, scratches and nicks on many of the drawers. Oak has no issues. It is surprising to see how quickly they can become damaged but realize you can easily replace over time and the cost is considerably less than custom.