Swim, sea invasion, huge fleet - why? It's the Swedes who would need to do swimming after Russians airdropped VDV onto Gotland in a surprise attack like they did in Hostomel, secured Visby airport, and started landing heavy equipment with Il-76 transports. Russian operation at securing Hostomel airport outside of Kyiv failed because the nearby Ukrainian forces immediately counterattacked. Until recently, Sweden had no military presence on Gotland and the island was entirely undefended.

The only wrong thing here is the idea that the invasion of Gotland would have to look like Normandy landings.