What will help more - certificates or projects?
Both hold equal relevance. Projects help to show you practical hands on your technical skills. It would also highlight some of your interpersonal skills like team work and Cooperation.
On other hand certification gives authenticity to your skills. It also show that you have curiosity to learn
Personally, I believe that projects add more value. It shows that you have taken action on the skills that you have previously learnt. It also provides a hands-on and practical experience.
Certificates are good to develop skills and get them authenticated, but only provides a theoretical knowledge in many cases.
This depends on the experience level of the individual. Someone with zero experience won’t have any projects to mention but I would expect someone with 5 years of experience to have actually done something in that time. In software development (my field), experience will generally be more valuable than certifications.
Further, if they have a degree, I would normally be more interested in that than a certification, unless the degree was years old and the certification was new.