Seeing as the difference was 1.89%, even marginally less effective campaigning would've doubtless resulted in a vote to remain in the EU.
On the other hand Trump supporters so seem to think he is absolutely wonderful - some sort of messiah.
But it's far from the support people have for Trump.
AT the last election the parties that got the biggest increases in their share of the vote were Reform and Green. Two very different parties and they have little in common other than not being Labour or the Conservatives. I suspect they would have done even better without a FPTP system.
https://www.bbc.co.uk/news/election/2024/uk/results (scroll down to see a graph of changes in vote percentage of votes cast).
FPTP also benefits parties with strong regional hotspots, such as Labour in cities.