The thing to remember in stores is that they either move fish on quite quickly so if they are crammed in or over stocked for a few weeks thats just part of how the hobby works for the stores to make money.
If you are talking about store show tanks, this can often be done in stores to inspire and aspire to but also not be a permanent fixture - stores also have lots of tanks to take out fish if they get an issue or need to separate one quickly which is not always possible at home.
Hardness is an issue that a lot of people do ignore but I think is one of the most important, with really soft water like you seem to have that is great for a big mix of species so you can lean into that and keeping fish that thrive in soft water will make your life much easier. For the opposite reasons I have really hard water so am starting to keep only hard water fish and its proving quite a bit simpler.
I have to admit I'm remembering some of our past conversations and you see to get through fish quite quickly and don't often take our advice on board - we will always be here to help but if you are fixated on what you want to do is it something we can really change your mind on? I like to think that the core of this forum is fish welfare and when we give out recommendations and parameters to work within and there are great combinations that will balance what you want from the tank with what your fish need but it feels like you just swerve past a lot of this - your Gymnogeophagus is a good example, even the quickest of googles would have shown you they are not a community cichlid because of the cooling situation, its maybe also a sign that your LFS is not 100% reliable source of info if they didnt mention this either.
https://www.seriouslyfish.com/species/gymnogeophagus-balzanii/
Check out the section on water conditions and also the bit in the notes too.
Just so I'm not all negative if I had a 5ft, 580litre with softwater and looking for 4 big cichlids to get to co-exist I'd possibly go down the route of a mixed Severum tank? A mix of Golds, Greens and Reds, all the same species just different strains - great personality reasonably peaceful, grow up well together and quite predictable. You might have some that cant live with other cichlids so be ready for that, you might also get some breeding but in a 5 foot tank it should be ok. You would still want to mix in a community of characins and catfish around them though to make sure they were confident in their tank, big tetras like Columbians would be great or Hemiodus species, Silver Dollars maybe? but might be too big over all with the cichlids in there. Headstanders would be nice too - I kept a school of Annostomus Ternetzi with my Severum but Marbled Headstanders would work too, need to keep at least 6 but more is better and then for catfish on the bottom to stir things up something like Hoplos or Pictus Catfish would be a good choice.
Maybe something like
4 Severums
20 Columbian Tetras
8 Marbled Headstanders
8 Pictus Catfish
Its a shame you have softwater as I think you'd really enjoy Malawi Cichlids - an all male Peacock and Hap tank is probably what you are looking for in all honesty. This is a pretty decent example (though don't have the Mbuna like she does).
Wills
