The least invasive process here would be bleaching. But since you don’t want to opt for that then you could go for veneers for the front 6-8 teeth.
Veneers are less invasive than crowns and can be done in 2 - 3 appointments.
Next Steps
Visit the specialist for an assessment of the same.
Health Tips
Once you get veneers, oral hygiene is not an option. You have to floss to maintain the veneers and keep the teeth healthy!
Water flosser at night goes a long way.