We always just split the bill equally. On the odd occasion that someone buys the 2000€ bottle of wine then that’s their problem - even if they shared a bit. The larger the group the smaller the discrepancies in general although I’m not keen on large groups. Hey ho, go with the flow!
Edit: Having read a bit more of the thread I would say that when we go out we get a couple of beers somewhere so we have a rota, then we find a restaurant split the bill) then one of us buys a round of drinks on the way home. Usually works out. Coffee stops much the same one of us pays then next one and so on…..