I'd watch them 4, 5, 6, 7, 8, 9, 1, 2, 3.
The reason being that the originals are still the best and you don't need the back story to enjoy them.
Then 7-9 are good and better than 1-3.
Once you've watched those and into the Star Wars vibe you're more inclined to be forgiving about 1-3 and interested in the back story (even if you spot some plot continuity errors with the original movies).
It's not tbf that 1-3 are shit movies - they just suffer in comparison to the others.
After that if your still interested I'd watch Rogue One which is a side movie that happens at the same time as 4.
Of all the new movies it's the best by far and stands as a good movie in its own right.
I'd avoid Solo though (the Han Solo spin off) if you're paying for it - if it's free it's an ok watch but it's the worst of the bunch and it doesn't even have Jar Jar Binks in it....you'll understand that reference when you watch.
Happy viewing OP and may the force be with you....