Im always in every save having problems with taking UK, I tried these things:

1. Paratroopers - I only got one successful attempt with them and I fail to reproduce it, I assume it worked one time because when I sent them there were no troops in that location, successfully taking 2 ports.
2. Taking Ireland - I saw many people say "take ireland", so I did it, but what then? You still need naval invasion to get to UK land because there is no direct connection between ireland island and uk island, taking ireland achieves nothing.
3. Build submarines only - the screenshot you're seeing is my current attempt at this, I first took iceland in 1936 and relocated all my subs there (I did it because between iceland and nearest uk land Its only ocean biome, which is best for subs and Its only 2 tiles). I built only convoys and submarines, got improved submarine chassis because I saw someone say AI cant detect them, refitted all of my subs to them and well, I lost half of my entire fleet in one week.

In every attempt I built a lot of fighters, CAS and naval bombers to reduce british fleet but it only helps slightly. Is building an actual fleet the only option for invading uk? Or there's another way that I didn't try out?

Also don't ask why luxembourg still exists, it now only does on this image.

How do I go about taking UK?