Pram/pushchair advice

Hey, I’m just after a bit of advice. I’ve currently got a nuna travel system which I absolutely love, and the pram works really well on tarmac/smooth ground. The wheels are very small though, and if I’m somewhere a bit more uneven like on grass or stones, it just doesn’t wheel very well. Does anyone have a recommendation for a pram that’s good for that kind of terrain? I don’t want to spend a fortune but also don’t want to ruin the nuna! Thank you 😀