I'm not sure the Ioniq's charging rate would cause me any big problems.
Looking at it from a practical POV, I've driven ~80 mile range EVs for four years now. In that time, the furthest single journey has been 185 miles. That needed three stops. The Ioniq may have been able to do that journey without a charge (the Leaf averaged 4.5 mi/kWh, so the Ioniq would likely be around 5 mi/kWh). At worst, it would need one short stop.
There's one journey I haven't attempted in the EVs I've owned; the 325 miles journey to see my Grandparents. In the Leaf or Zoe, this would mean around 5 stops, so I've been using the train instead. In the Ioniq, it would be 2 stops, which is fine. Anything much beyond that distance, 30kW charging would start to get annoying.
The only time I can picture 30kW really being a problem for me is when I got home with low charge and need to go out again quickly; there's a good rapid charger round the corner from my house. But I only have to do this because the Leaf's winter range is dire. If I charge the Ioniq every night, it shouldn't happen.
I'm really tempted. I reckon I've got £2k equity in the Leaf, less maybe £500 in repair costs (some swine scraped my car and scarpered). So enough to cover the initial payment. Then it's an extra £39/month + £150 admin + GAP insurance. Not bad for how much better the spec is.