12 year old won't go anywhere or do anything unless forced.

I wouldn't be so strict on the PlayStation- obvs not free access but it's the way young teen boys socialize nowadays. It's not as brain-numbing as endless TikTok scrolling, it's more creative. At your son's age mine was just playing Minecraft, so no violence etc. He may feel excluded at school if he doesn't have that avenue to make connections.

My oldest was similar, it was all tied into anxiety and sheer paralysis about his peers' opinions. Covid obviously made everything worse. He quit a sport he enjoyed because of some off-the-cuff remark someone made to him. I was very concerned that I wasn't adding another layer of judgement to that he was piling on to himself.

He's improved over the years, 19 now and working, will be starting uni in September all going well. He's still more introverted but that's his personality type... he has friends and ambitions.

I think you're unreasonable to force him. Not all kids like structured activity. I was pushed into them as a child and it was exhausting. I was left feeling guilty because I didn't enjoy it and as i wasn't good at it I felt I was disappointing my parents.
I've tried a different approach with my kids. I let them choose what to do with their free time and how much extracurricular stuff they do. I have 2 teenage boys (both autistic), one of whom barely goes out and one who is relatively sociable but prefers one to one time with friends over group activities. And my pre teen girl is very active and sociable and goes to several clubs and groups, as well as playing with friends.

They are all different people. The boys are very different to how I was as a teen but actually that's ok.

Encourage some hobbies he can do indoors/at home.
Lego, reading, art, cooking, gardening etc.
Not everyone enjoys being out and about doing "activities".

Sometimes it’s best not to force it and let him get on with it (to an extent). Let him develop his own interests and let things be his idea. Puberty is also exhausting - I very much just wanted to be left alone during my downtime a lot of the time. I definitely didn’t have a zest for life. Give him some space

He's a 12 year old boy, it's a case of wait and hope puberty cures him or put him out of your his misery now. 😆

This is a very unpopular parenting opinion but we left DS to get on with it at 12 yo and he didn't go out, wouldn't join clubs and had an amount of screen time that would make you faint.

It was all slightly different as he was 12 coming out of pandemic and all our brilliant screen time boundaries had gone to pot in lockdown.

We did know he had friends at school - he was on line gaming with them in his endless screen time. and he would drop everything to go out if a friend was available - bikes/ tennis/ swimming. We'd occasionally drag him or bribe him to a family outing. And beyond that trusted it would come good.

He did this sudden maturity leap at 13 1/2 - (also puberty) changed about 50% of his friendship group. Registered for DofE. Joined a school club.

So I would say as long as the basics are there - keep making it clear you expect him to be out and about doing things, facilitate the smallest steps in the right direction and try not to worry too much.

(Disclaimer - he is still only 14 it could still all go horribly wrong).

Don't give up, he's too young to lose guidance on how full and exciting life can be.

Does he get too much choice and control maybe, why is staying home instead of going to sports camp an option? My DD is 12 and I think most of her peers who are stuck and do nothing have always been given the control/pressure to decide what to do. It's too much and they don't have the imagination or experience to fill their time.

In your shoes I think friends are the key. Get him doing things with his friends, going in and out of each others houses, taking a football to the park, booking a tennis court for them etc.

How much access to screens does he have? Is he choosing to stay in so he can have screen time?

How much exercise do you do OP? How much does he see you/either parent having fun outside, being active etc?