I know nothing of Xbox or GamePass so could you dumb this down for me?
Like
this?
I just bought the £1 trial, so I already screwed up?
TL/DR: Let it expire then do those steps, but might be tiny bit more for 1 month GamePass Ultimate code if they don't let you use a $1 trial.
Xbox Gold is for consoles ($60 a year)
Xbox Game Pass is for consoles ($10 a month)
PC GamePass is for PCs and includes PC EA Play ($10 a month)
Game Pass Ultimate includes PC Gamepass, PC EA Play, Xbox Gold, Xbox GamePass, and Console EA Play and Cloud Streaming. ($15 a month)
If you want GamePass Ultimate, then the best way of doing it is how they listed it out. If you did not stock up on Live Gold before hand, then let the GamePass Ultimate expire. Once it's expired, you load up on Xbox Gold for 3 years, then redeem 1 month of GamePass Ultimate. When done in that order, the upgrade conversion is 1 to 1.
If you only want PC GamePass then the math to figure out if GamePass Ultimate is worth it becomes comparing the following two costs:
3 * ($45 to $60 for Gold Year) + $15 Ultimate = $180 + $15 = $195 for 3 years of GamePass Ultimate
3 * (12 * $10 month) = $360 for 3 years of only PC GamePass
3 * (12 * $15 month) = $540 for 3 years of GamePass Ultimate
The first Gold Conversion equation depends on how cheap you can get 1 year of Gold for. Even at the highest price you can see it maxes at $195 for 3 years of everything in GamePass Ultimate doing the conversion upgrade. It would be $360 just for PC GamePass. It would be $540 for GamePass Ultimate if you paid monthly.
If you want continuous service for 3 years then the conversion upgrade is where it's at. However, it may be in your interest to pick and choose what months you want it. Like maybe pick it up for just 2 to 4 months a year when you have time to play. All depends on how you think you could use it.