Looking at the Dutch site on my phone (Samsung S10) I noticed it took a little while to load compared to the nigh instant loading of the UK Gov variant. Looking at Page Insights [0] [1] tells a similar picture. Desktop time to interactive times of 0.4s Vs 3.5s and Mobile time to interactive times of 4.5s Vs 13.1s.
The Dutch website seems to spend a lot of that time running the Next JS framework stuff, which the Gov.uk variant does not. It might work quickly on fast computers, but even on modern phones it seems to visibly pause.
