Misunderstood
FPtP is used because YOU ARE NOT VOTING TO CHOOSE THE GOVERNMENT!!!!!1111!!! People really need to understand that. Ofc you can choose to use your vote as if you were voting for to choose the government, but that's not what is intended and so you don't get the intended effect from your vote.
You vote for YOUR MP to represent your needs in Parliament. The fact that the political party with the most representatives happens to form a government is really a seperate issue. You don't need to worry about such details generally as it really doesn't matter, until that is you're deciding on an electoral system.
PR is about electing a national government. So, you have to decide between someone that will (hopefully) support you and your local area, and some party that will (hopefully) support your country. The problem with PR is that the wannabe MPs don't worry about annoying the locals, whereas an MP elected under FPtP can't afford to ****-off his/her constituents as they'll be out of a job.
I like some aspects of both tbh, and issues with both. You should be aware however that the ppl pushing PR aren't doing so to help you in your daily life. They're doing so to increase their own power base. Same for those pushing to keep FPtP too.