Three pairs of gloves and I have no idea which are actually protecting anything: what matters?

How to judge one in a shop, since the marketing tells you almost nothing:

Look for a certification mark rather than a description. There is a European standard for motorcycle gloves with levels, and a certified glove has been tested for abrasion, tear, seam strength and impact. A glove without one has been tested by nobody. This is the closest thing to the helmet rating you are used to, and most riders do not know it exists.

Check the palm by feel. Two layers, or a visible reinforcement patch. If the palm is a single layer of thin leather, it is a driving glove.

Pull the wrist closure and try to drag the glove off with your other hand. If it comes off easily, it will come off in a slide.

Fit is protection, not comfort. A loose glove bunches and the material shifts away from where the impact is. Snug with no pressure points, fingers reaching the end without pressing, and able to operate the controls without a fight.

Work the levers while wearing them before buying. A protective glove you cannot brake precisely in is a bad trade.

And on the three you own: the leather pair with the wrist strap is probably the only real one. The waterproof pair bought in a hurry is worth checking against the list above.

You have it backwards in a common way: knuckle armour is the least important part and the palm is the most.

In a fall, hands go out. What contacts the road is the palm and the outside edge of the hand, at speed, and what happens next is abrasion and then the hand catching and twisting. Knuckles hit things occasionally; palms hit the road nearly every time.

So what actually matters, in order:

Palm abrasion resistance and reinforcement. A double layer of leather across the palm and the heel of the hand.

A slider or a smooth reinforced patch on the heel of the palm. This is the piece that lets the hand skid rather than grip and twist, and twisting is where wrist and scaphoid injuries come from. It is the single feature I would not buy without and it is absent from most cheap gloves.

A wrist closure that keeps the glove on. A glove that comes off during a slide has done nothing. Anything without a proper wrist retention strap is decorative.

Coverage past the wrist bone.

Stitching and seam placement, internal or protected seams, because exposed stitching abrades first and then the glove opens.

Knuckle armour, genuinely useful and last on this list.

The honest answer on hot weather, since everybody wants to hear that they can have both.

Ventilated gloves are a compromise and they should be chosen as one. Mesh where the leather would be is less material in the places that matter. A good summer glove keeps the palm and the outer edge fully covered and vents the back of the hand and between the fingers, which is where most of the cooling comes from anyway and where least protection is needed.

A glove that is mesh across the palm is not a hot weather compromise, it is a bad glove.

So the buying rule for summer: vent the back, never the palm. Perforated leather is a good middle option - it breathes noticeably better than solid leather and keeps the abrasion resistance.

On the waterproof pair: waterproof membranes make gloves bulkier and less tactile, and the cheap ones are usually protective in name only. If you ride in rain regularly, it is worth having a proper pair; if it is occasional, over-gloves that go on top of your good gloves are a cheaper and better answer.

Two pairs covers almost everyone: a proper summer glove and a proper winter or all-season one. Three mediocre pairs is the arrangement most people drift into, and it is worse than two good ones.