Hi Jackie! Not a whole lot you can do. Ants are 'hard wired' to protect the nest. They will die for the Queen. Wear long sleeves. Yes you can buy all kinds of bug spray but they leave you a greasy mess.

There's diatomaceous earth or I've often read that ants hate ground cinnamon. I've used cinnamon & although I didn't closely check things I have fairly few now compared to a few years back when I'd get an annual explosion of flying ants & loads on my blackcurrants.
There's always poisons you can buy too

Could you empty the pot, save the planting and move the remainder containing the nest so that you don't need to kill them.
Perhaps your pot is too big for that.

This might interest you:

'Ants are generally considered one of the good bugs, but the verdict is still out for some gardeners. Ants don't normally cause problems in the garden on their own and they won't eat or harm your plants. Ants can be beneficial pollinators and they eat the bad bugs that do damage to your plants.'

Garden Ants: Friends or Foes? - Get Busy Gardening
https://getbusygardening.com/garden-ants-friends-or-foes/

Soak the pots - ants hate too much wet. Otherwise (and a better solution) if the pots are of a size to do this, remove what plants are in there and tip the soil out - then run! I'm serious... leave the mess for an hour or three so they can make their escape, then you can spread that soil over the borders to get rid of it. In the meantime, clean the pots, put a layer of something like a jeycloth or some weed membrane in the bottom, fill up with fresh potting soil and replant. And the most important bit of all, stand the pots on something, pot feet, bits of broken slate, anything that will give half an inch clearance beneath the pot so they're not standing directly on your patio or whatever.This will deter any further invasions, especially if you dust beneath with ant powder periodically.

Whilst they don't eat roots or plants,they will chew through roots to make more room for their nests,so you might find very little root on some of the plants anyway, whatever they are. I once lost a rhododendron in a pot because of ants - the plant looked sick and there were lots of black flecks round the base of the pot, and when I turned it out, it was a massive ants nest and only two little, short roots left on the rhodie...

I lost a large lavender the same way.

Last year, I wanted to repot my heuchera which had become too big for the pot. As I took it from the pot, a mass of ants were everywhere! I panicked and tipped the soil onto the garden bed. They ran everywhere. I bought some little discs, which were safe to use in the garden with our cats and other wildlife. The discs are covered in a sweet liquid they like, they then take it back to the nest and it kills them. Within two or three days they worked. My heuchera roots had been eaten.

Thanks for your input about the ant's, I weeded it before the ants were active & topped up with soil & will leave them alone seeing they don't do any harm to my Magnolia that is in a very big pot :o))
Cor! My Magnolia has had its best year this year, lots of blooms :o))
I will put some pics in my Pictures, & of my Beautiful Sunking tree too :o)) xx