Sweden is portrayed as beacon of human rights, let's use them as an example.
replyhttps://www.reuters.com/world/sweden-tighten-citizenship-rul...
The rules now are tougher than US rules for citizenship. Sweden (like e.g., Norway) has a 8 year wait vs US's 5 year wait.
Sweden has minimum income requirements, none in the US.
That is for a different scenario. It means that if you already have a residence permit, you have to wait 8 years before you can apply for citizenship. OP is talking about marriage green card. For 75% of cases in Sweden it is less than 15 months to get a residence permit.
reply[1] https://www.migrationsverket.se/en/you-want-to-apply/live-wi...