Hi. That is a really nice scape. Well done!
I have to think tiger barbs will be nippier when in small numbers. In big groups, their aggression is diluted. Unfortunately, you haven’t the room for a decent group of six inch long semi-aggressive fish including the other fish currently in there. I’d consider rehoming the barbs honestly, otherwise you’ll end up with only one or two monster barbs, and missing tank mates most likely.
I would prioritise getting another species of bottom dweller or stocking up on the bottom dwelling species currently in the tank. The latter of these two options would be best. Six minimum is the general rule, but I don’t believe this rule actually works or makes the fish happier than if it were in a group of four or five.
Aqadvisor isn’t a good source because it doesn’t take the bioload or temperament of fish into consideration. It only goes by the size of the fish relative to the tank volume.