www.cornwall.gov.uk/environment/animal-welfare-and-enforcement/dogs-on-beaches/?fbclid=IwAR1KoAatxosu72rBgRXyuTnUkYblTgC8ZtGdhG0fP5tEy_I01VIxgt-e1iw
This is the Cornwall council website for when dogs are allowed on beaches. Most of the st ives beaches dogs are banned from July to end of August
You aren't far from Gwithian Towans which is firm under foot if a little hilly. Just watch out for adders but they tend to be in the more off piste areas.
Porthkidney beach on the estuary at Lelant is dog friendly all year round. Drive down the track by the church and over the golf course l. It's steps to get down but not many. There's also a track which you can take behind the beach which might be easier. Sorry can't remember it's been a while since we used it as it's good for when the tide is high
I think the estuary on the other side on hayle is also dog friendly . If you park near the George V walk. Another straight road but dog friendly walk not too far walk. If you go in the opposite direction you get to the access to the estuary.
There's also the far end of the beach at long rock. And the walk from the car park at long rock towards there is good under foot
Towards helston there's the penrose estate which is either tarmaced or hard gravel. There's loads of walks around there to do. Involving loe bar. It's about 40 mins from at ives. Most of it is a National Trust so check out their website
Not at all beachy there is the great flat load towards Redruth/ Camborne. It's good under foot and you can do as much or as little as you want.
Over towards Truro similar to Penrose there is Trelissick which is also National trust. It is not as good underfoot but there are some nice paths and smells to sniff.
Please let me know if you want any further ideas, and please refer to local websites and maps for clear directions.