I have to start with the fact that the Xplory is VERY VERY upright, actually one of the most upright strollers on the market, meaning that increasing in size of the seat and thus changing the stroller type will definitely mean a less upright position, unfortunately. Also important is the fact that if you truly need to use the stroler up to 22/25 kg of your child, you need to make compromises pretty much everywhere as a 22-25 kilogram kid will not fit into most strollers comfortably, and therefore the priority of an upright sitting will have to make a step back as even this seat size priority will not be easy to reach. And all that with quite a limited budget, meaning either thinking of a pre-owned pushchair or very little to check if needing the larger seat size.
I will, therefore, concentrate on the roomy models and try to be upright - kind of - to check as much of your priorities as possible. But I am strongly suggesting going in a store and looking around in real life just to see you don't really have that many options, and what is there will be ok with one of your requirements and not with the other.
I'll start with an- ABC Dewign Avus which I believe should tick most of your boxes, perhaps is just not extremely all-terrain (but shouldn't be harsher than an Xplory). Then, rather upright while very spacious is the Valco Trend Sport which has a very very spacious seat but no suspension, however, with the inflatable SPORT wheels it can ride rather comfortably even on bumps. I also quite like the Gesslein S4 which is nice in terms of wheels and suspension particularly. And if you don't mind a second-hand solution, I would also check the Cybex Iris or Agis lines which are superbly roomy, and even if not with an incredible amount of suspension, they will last you with even a large child.
P.S. I didn't concentrate on the rain cover included as you can buy a universal one pretty much in any baby shop, and to limit the choices even more would not be wise in this situation, I think ^_^