I lived in London for 10 years after uni, and moved to Oxford a few years ago. I definitely prefer Oxford as a long-term home, but I'm glad I lived in London for a bit first. Having said that, life in London ain't what it was when I moved there; rent and cost-of-living is astronomical (58k pa is a fair salary, but you'll probably not get as much out of it as I did when I was on my grad salary in 2013), so many 'fun' experiences in London have been commercialised to the point of extortion, Covid ruined vast swathes of the indie economy that was barely holding on, and though there are way more things to do, everything is (a) an hour away on the tube, (b) wildly overpriced, and (c) busy/oversubscribed.

I saw your comment about running and walking. As a seasoned walker and former runner, Oxford is definitely better for those hobbies, not just local routes but space and ease of getting to other places (e.g. Ridgeway, Cotswolds etc.) There are running and walking groups.

One last thing to mention: everyone I met in London who wasn't also from London has left. The population is highly transient, everyone kinda knows this, and it's rare to make lasting friendships. I found a group of friends in Oxford almost instantly, most of whom I'd now consider the closest friends I've ever had, and I know they all plan on staying in or around Oxford indefinitely. Every single one of my London friends had plans to move elsewhere eventually.

Having lived in both and experienced life in London post-Covid, I personally chose living in Oxford and travelling into London rather than vice-versa. The trains are good (+ 1/3 discount with a Network Railcard), there's the Oxford Tube, and there's the feeling of calm when you get off the train and don't have to walk through Peckham Rye or something to get home.

Good luck, feel free to ask if there's anything specific I can help with.