The infant carriers are the same in Sweden. They use the same car seat regulation as we do here, so they are the same brands and models. The main difference is the next stage, most British parents tend to move into a forward facing seat, whereas Swedish children are almost all rear facing until around 3 or 4 years of age (some until more like 6) - this is according to an observational study Besafe did a couple of years ago, so it's up to date information. Advice in Sweden is to rear face until 4, and their market history is almost exclusively rear facing seats. Because they use the same regulations as here, it's perfectly legal to buy and use a forward facing seat, but I understand that culturally it is frowned upon and is advised against by salespeople, consumer organisations, paediatricians, their equivalent of health visitors etc.
Likewise it is perfectly legal to buy, sell and use the Swedish style rear facing seats which accommodate up to approximately 4 or 6 years in the UK. Some of these are even mainstream now, like the seats you can get which spin in either direction, although these are not commonly used on the front seat because they are isofix, and not many cars have isofix points in the front seat. The seats up to 6 years are more difficult to find and less well-known, because you tend to have to buy them from specialists, but the Britax models are actually made in the UK and then most of them are shipped to Sweden and Norway. They also appear on all the manufacturers' UK websites nowadays (you go back 10 years, and they didn't, even the ones which were produced in this country, and even though they have been legal to use here all along. It was like some kind of dirty little secret!)
The website that article is on is an online retailer specialising in international exports of those Swedish style longer-rear facing seats. They do stress that the recommendation that the front seat is as safe applies only to children in rear facing seats, whether they are infant carriers or these larger seats for older children, and they say that it does not apply to forward facing children. This is why (it was explained to me) most UK based sites will say the back is safest, because the assumption is that children are forward facing. And this is a problem because they are either in danger from the airbag or they are not able to be protected by the airbag like an adult passenger would be. The rear facing child doesn't need the protection from the airbag, as long as the passenger compartment doesn't suffer intrusion, because the shell of the seat performs that function instead.
As for what kind of cars are driven in Sweden, I couldn't tell you offhand, but I doubt they are all completely different. I did just quickly google it and came up with this:
Sweden
www.statista.com/statistics/424960/leading-passenger-car-models-in-sweden/
UK
www.autoexpress.co.uk/news/94280/best-selling-cars-2021
So yes, a higher proportion of Volvos in Sweden, but Golf, Quashqai, Kia etc in there as well, so I don't think all Swedes are driving tank-like Volvos.