@Panicmode1 hope you had a lovely birthday celebration!
Regarding accommodation, as others have said, this varies college to college at Ox and Cam.
DS1 (C) was allocated a tiny, en suite, top floor room for his first year, right beside the corridor door that banged loudly every time anyone went in and out of the corridor. Freshers decided that this corridor would be party central and played loud music all night long outside his room. This was the days of Covid and any gatherings happened only on corridor floors where students also ate from takeaway plastic trays sitting on the corridor floors. So that was a tricky start for him, as he likes peace and quiet.
Don't get me started on food....let's just say that by year 2, he was buying and cooking all his own food in the tiny kitchen on his corridor and one of the only times he ate college food - other than at formal hall dinners - he got really bad food poisoning.
Accommodation bills were sent within a few days of each term. In Years 2 and 3, he had to list a choice of accommodation and each time got his last/ 5th choice, with no en suite but in a nicer, quieter part of the college and also the very cheapest too. In fact, his accommodation costs must have been amongst the cheapest student accommodation in the UK, which was great. He got his bedding and towel provided by college and washed/ changed each week too.
DS2 (O) was allocated a massive but non-en suite room in his first year, very peaceful but not so cheap as DS1's and in fact each year, DS2's Oxford accommodation costs were quite a bit more than DS1's but still really good rates for a student. His college had a proper ballot system so that if you'd not got your first choice the previous year, you'd have a better chance of this the next year. In Years 2 and 3, he got en suite rooms, again, far far larger than DS1's. In his final year, he had a massive room about 4 to 5 times the size of his tiny room back home and with two beds as well that could be made into a double. He provided his own bedding each year.
Food at his college has to be about the best I've ever had when eating out (For me - one formal hall and one graduation lunch only, however, during his entire 3 years there). However, he too made a lot of his own food in his second and third year in the kitchen for his college accommodation block.
Both had to clear out their entire room at the end of each term, so there was a lot of packing and unpacking to do across the three years. Both enjoyed being able to live in college for all three years and this worked out very well for them. Parking at each of their colleges was always fine and plentiful for parents.
Regarding cycling, both used their bikes a lot at Ox and Cam and used two strong locks to ensure no thefts. Both are used to cycling and weren't worried about traffic but had a sensible attitude towards safety and no accidents.
It's so exciting, by proxy, hearing about all those with DCs starting out at O & C. I wish my two could do it all over again and they really loved their time there.