I have never thought about the fact that manhole covers need to hold up to weight. Of course they do and it's perfectly normal and sensible. It's just not a thought I've ever had.
Technically, the walls of the manholes, in turn, support the weight of the cover and whatever load is on top of it. The entire manhole is a weight-bearing structure.
For formula one races they weld them down to stop the cars incredible downforce from sucking them up into the air. Even then they sometimes get torn up and thrown around.
Manhole covers are also a common exercise for engineering students. Like designing one that can hold x amount of weight with a specific set of limitations and/or requirements.
Obviously in the dystopia of Night City, lighter weight manhole covers were approved for road use purely to cut costs, and any deformed or destroyed covers have the cost offloaded to the poor rube who last ran them over.
Most of the complaints about bugs in this game seemed overblown
You should've tried it on PS4 at release. It was glorious. I did have a ton of fun because of the bugs (couldn't progress in the game much) but if I had paid for it I would've been pissed
And nowadays they are supplemented and partially superseded by European EN directives. This is the kind of stuff that hardly anyone realizes but is enormously helpful in everyday life. Your toilet seat breaks, you just go ahead and buy a new one. Its mount points, dimensions, and load bearing characteristics are standardized so no need to get a degree in toiletology or whatever. Just buy any one you like. Same idea with light bulbs, printer paper, piping connections, door jambs, etc. etc. Standardization makes life SO much easier.