Just weighed the wheels I’ve had built around the Condor 24″ MTB rims and some old Deore hubs I found on eBay. Built-up wheels (hubs + spokes + rims + tape) are ~900g and ~1100g. The wheel builder said the rims are most likely Alex rims from looking at them, which is fairly likely.
For comparison the stock Carrera wheels are ~1kg and ~1.2kg, with a 7-speed hub, fairly unlikely to go up tubeless, and rust patches. The Superstar Fuel/Crest combo are 721g/902g but are also £300 a set so that’s ~400g lighter for ~£200.
The set I built used a Mk1 rear Bulb hub (spares box) a used OEM hub off ebay (~£5) and came out a similar weight to your deore set a little under 2kg for the pair, that was using PG spokes.
It was a similar £££s per gram type calculation, I almost certainly could have saved an easy 200g by buying nicer hubs and I could have had DB spokes for double the price and saved a bit of weight, but I really don’t think she would have appreciated the difference and for the price the rims are a competitive weight, not the lightest granted but to save another 100g per rim you are looking at quite a bit more spend…
I suppose if you’ve got kids already racing at the sharp end a 1600g wheelset is a worthwhile investment for them, but for more “average” kids just riding about with their tubby Dads 1.9-2kg is acceptable IMO…