I installed an iSpring RO500 tankless system under my kitchen sink. It does have it’s own faucet which displays TDS (total dissolved solids) as it dispenses. I don’t use the reverse osmosis water for my garden. We treat it with mineral drops for drinking water and for use in the fancy coffee machine. It feeds the ice cube maker which will hopefully extend the lifespan of that appliance. I’ll mix it with tap water for houseplants and the chile pepper plants I’m growing out on the deck. This RO unit has been a solid performer the last few years. Easy to change filter cartridges, tankless design saves space, much faster to fill than other RO systems. Costs more than some too…
My garden has no access to running water. I keep a 30+ gallon trash barrel filled via a hose connected to an exterior spigot. I let it sit overnight before using which helps when my municipal water supply is using chlorine (in the summer, iirc), but not when they switch back to chloramine. I just add nutes and adjust pH in a 5 gallon bucket before watering.