A concerned dad asking for help

Sorry if this is long, just need to vent and maybe get some ideas.

My son turned 15 in the spring and somewhere over the last school year he basically vanished into his room. He used to be a pretty active kid — rode his bike everywhere, was outside constantly. Now he’s home from school by 4, and unless I physically go up and drag him down for dinner, he’s in there gaming until I tell him it’s time for bed. Weekends are worse — he’ll go 10+ hours some days.

What worries me isn’t really the gaming itself, it’s everything around it. He’s stopped asking to see his friends in person (they all just play together online now, which I guess is “normal” these days but it still feels off to me). He seems tired all the time despite barely moving. He used to have decent energy and now he’s sluggish and irritable if I even bring up going outside.

I tried the direct approach — “let’s go for a bike ride” — and got told he’s “not a little kid anymore.” I tried bribery (new game if he does 30 mins of exercise a day) which worked for about a week before he lost interest. I even looked into whether some of these games have any kind of movement component built in (I know some VR stuff exists) but he’s not interested in switching set-ups.

Honestly I think part of it is I don’t want to nag him into hating me, but part of me also feels like if I don’t do something now this becomes his whole personality for years.

Anyone dealt with this and actually found something that clicked? Trying to figure out if this is a “give it time, it’s a phase” situation or something I need to be more proactive about.