There is a well-established academic finding, Arrow's Impossibility Theorem, which demonstrates that it is impossible to have a perfectly fair electoral system.
I agree with you generally about PR, but even with that system there are problems. To work it needs multimember consitutencies, because otherwise only the middle of the road candidates will be elected. But the size of the constituency influences the result. Look at the UK European elections. In the four member North East England constituency, the Greens have no chance of being elected whereas Caroline Lucas, their UK European leader, manages to get elected in South East England because in a much larger constituency the proportion of the votes needed to get in is much smaller.
European Elections also highlight the point that fair elections must allow voters to choose between candidates and not parties ("closed lists"). Otherwise large parties can put dodgy candidates at first place on their list so that they get eclected despite personal unpopularity.Again, in South East England Labour lost one of its two MEPs last time, If there had been individual voting I would have split my vote between the Greens to give a personal vote to the Labour MEP who lost his seat, because he had a particularly good record on helping East Kent and on transport issues. In practice, as I indicated by naming a Green candidate, the "closed list" leads to the middle-sized parties putting one big name candidate at the top of the list: any elected members elected from lower places become second class because electors do not know who they are.
Also, no election is fair and democratic if the registers are not accurate and if there are unfair election practices. The accuracy of the register in the UK is a matter for concern. recent provisions for proxy and postal voting are insecure. There have been several recent convictions of candidates who have tried to fiddle proxy or postal votes - how many more cases have gone undetected?
The democratic deficit for provincial English voters, who have no regional government (or rather an indirectly appointed one that nobody knows about) , and whose Westminster constituencies are larger than those elsewhere even though MPS form elsewher in Britain can interfere in English affairs devolved elewhere in the UK, is a scandal.
My personal feeling is that above all the electoral system should be fair and consistent. At present, in the UK there is a mess of first past the post for Westminster, "top-up" list systems for London, Scotland and Wales and "closed list" PR for Europe. There should preferably be PR using Single Transferrable Vote to choose between individual candidates in equally sized seats or first past the post, again in equally sized seats.
In short, I agree with you about PR. However, there are even more serious concerns about the UK electoral system which you should not overlook by focussing on the minutiae of different voting systems.