If every press-on set you have tried has slid sideways by day two, your nails are probably narrower than the kit assumed, and no glue in the world fixes a width problem.
Press-on kits are cut to an average nail bed. A standard 24-nail kit covers 12 sizes, but the run is weighted to the middle: lots of mediums, a couple of narrows as an afterthought. If your nail beds run narrow, the "closest" size in the box is a little too wide, so it bridges your nail's natural curve instead of hugging it. A bridged nail holds on at the edges only. Water gets under it in the shower, the edge lifts, and by mehndi night it is in your clutch, not on your hand.
How to know your size: take a soft measuring tape or a strip of paper and measure your widest nail, straight across the widest point, in millimetres. Do the same for your thumb and your pinky. Three numbers describe your whole hand better than any small-medium-large guess. Most kits assume an index or middle nail around 12 to 13 mm; narrow beds commonly measure 10 to 11.
What NUARA does differently: our size runs are weighted toward the narrow end, so the box spends its 24 nails where our customers actually are. Fit is the second of our four promises, and it is the one the whole line was founded on. And because a promise should be testable: measure your nails, check our chart, and if we do not cover you, tell us at hello@nuara.ca. Size data from real hands decides what we make next.