Sadly many new owners have wrong expectations from seeing all those cuddling and petting videos on social media.
Guinea pigs are prey animals, they are not born as living cuddly toys. By far not all piggies will ever enjy being cuddled, especially not when they are free ranging!
Take hope from the fact that your piggies trust you (they take food from you). To get more, takes much longer and requires patience and persistence. Never push a piggy any further than it wants to go and respect it when it tells you that it doesn't like something. In the end, you will get a lot further, develop a much deeper bond and gain absolute trust by respecting your piggies as their own personalities with their own needs and wishes rather than just a living extension of your own preconceptions and desires.
Trying to see things from a guinea pig perspective and not just a human perspective will open your mind and make you a much more understanding person in the long term.
You may find these guides here helpful:
Understanding Prey Animal Instincts, Guinea Pig Whispering And Cuddling Tips
How To Pick Up And Weigh Your Guinea Pig
Bonding: Illustrated Dominance Behaviours And Dynamics