I've spoken to colleagues and family who have them and they all regret it.
This is completely untrue, we've run an e-Niro as our only family car for 2.5 years, and it's taken everything we've thrown at it, family of 4 on camping trips with a big dog in the boot and the roof loaded with tents/sleeping bags/etc. tip runs, loaded up with bags of cement and timber from B&Q, etc. It's no less practical than any other similar sized hatchback, regardless of the fuel type.
"you can't have the heater on without the mileage dipping",
Yup, this is true, it's not so much of an issue on newer cars with bigger batteries, but certainly, on the first gen Leaf/Zoe it could be a decent chunk of range. If you're looking at spending £10-20k then I doubt you'll be considering one of those though.
This is only really relevant in the winter, so if you are doing lots of very long trips in the winter then this is certainly a concern (along with the fact you'll lose ~30% range due to the cold weather anyway). In the summer then having the A/C on will hit the range (same as in an ICE...), although to a much lesser extent than heating; when it's warmer you'll be able to go further on a charge anyway.
"charging takes 45 minutes plus".
This is both true and isn't. If you're stopping at a motorway services with rapid chargers (e.g. 100+kw), most recent EVs will gain 100+ miles in the time it takes to take the kids to the toilet, grab a quick drink/snack, and stretch your legs for 5 minutes, so for practical purposes, it takes you ~2 minutes to charge (~1 min to plug it in and start the charge, ~1 min to end the charge and unplug). If you're going to the beach or something, then it can require some additional planning, and you might need to consider parking at a "non-optimum" location, but that aside, again you're looking at a couple of minutes to plug the car in when you park, and unplug it before you leave.
Recent example - we went camping in Wales last summer, stopped at Welshpool to charge (TBH we didn't actually need it, but figured it would give us a bit more buffer to play with while we were away), by the time I'd let the dog stretch her legs and do her business, and the kids and my partner had been to the loo and grabbed some snacks from the shop, the car was back up to ~90%. We got to our campsite with plenty of range left.
A couple of days in, we went to the beach at Fairbourne; now there is a car park right next to the beach, which we would have normally parked at; however since I thought we could do with a charge, I dropped my partner and the kids off at the closer car park, and parked at a different car park with a charger. This was pretty inconvenient, as it was at least 4 minutes walk away from the beach. Left the car there for most of the day - which was fine as it was only a 7kw charger - and IIRC it was up to ~70% when we got back to it later.
When we headed home we stopped at Welshpool again - same story, by the time the kids had been toileted and fed, and the dog had been sorted out, the car had more than enough range to get us home.
Total time spent "actively" charging: probably less than 15 minutes (including the walk from/to the further car park) over 300+ miles/5 days. This wasn't me driving for efficiency either - CC set to 75 on the motorway where possible, and with the car fully loaded and a massive roof bag on top killing the aerodynamics!
7-8 years ago I'd agree with charging being a pain; when we had the Zoe back in 2019/2020, it was a whole different ballgame, the car was slow to charge and there were very few chargers around! Since having the Niro, I've had to actively wait for a charge once, and that's only because all of the 150kw chargers at the services we stopped at weren't working, so we were stuck on the slower 50kw. Even then it was only an extra 30 minutes, and it just meant we ended up having lunch earlier than planned