Agreed. There are numerous alternative voting systems out there, but I would say "The best alternative to FPTP is the one that has the strongest chance of happening".

With that in mind, I think it is worth looking at which voting reform proposals have been rejected before, and what argument their opponents used. My impression is that cost and complexity tend to be the biggest persuaders, so strategically it makes sense to support a voting system where the ballot marking and counting processes are as familiar as possible.

As a concrete proposal, I suggest a system where people fill in ballots exactly as in FPTP, and the results are counted in exactly the same way, but then the candidate with the least votes gets to reassign their votes to another candidate of their choice, and so on until one candidate receives a majority of votes.