connecting via ssh to wordpress ami

as you can see from the link https://bitnami.com/stack/wordpress/cloud/aws/amis Wordpress AMI s are based on Debian

and while creating app you can select security rules that who can connect with SSH to the image

So review NSG first before connecting with SSH then follow these steps to connect

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AccessingInstancesLinux.html

Can you connect with certificate not password Please follow https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/putty.html

yes, the ami is https://aws.amazon.com/marketplace/pp/prodview-bzstv3wbn5wkq?sr=0-1&ref_=beagle&applicationId=AWS-EC2-Console but when trying to connect via dashboard I get this:

Furthermore, I can't connect via putty for example because I don't have the instance password

Are the following AMIs used?
If so, I think SSH is possible since you are using Debian 11.
https://aws.amazon.com/marketplace/pp/prodview-bzstv3wbn5wkq?sr=0-1&ref_=beagle&applicationId=AWS-EC2-Console

You have probably set up a key pair when you created EC2, so SSH using that key pair.
SSH is possible using the methods in the following document.
Also, configure the inbound rules of the EC2 security group to allow SSH.
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AccessingInstancesLinux.html