Definitely wood, but bigger than the toothpicks chat gpt suggested.

The picture with the curtains is not altered, that’s the current size. Should I beef them up?

Round wood columns slightly smaller than the chat gpt image would look best.

Yes, beef them up!
My pergola is approx 12’ x 30’ and my columns are 9’ tall with a gradual taper from 8” square at the bottom to 5” at the top. They look good-
The wood you have is a much better fit style wise for your house than those ornate Corinthian stone ones.
I’d expect those in a very large formally landscaped setting.

Depending on your climate, you might even want to consider a different material than wood, like fiberglass.
My original cypress columns rotted at their bases in under 5 years, so the builder copied them in concrete.
I live in very humid Florida, though.

Chat image is far too fussy, and far too bulky for the house. and roof .

What does the front elevation of the home look like look like? What's the locale?

Is it a lighting difference.....as to different stain appearances? Feels a bit heavily lidded. - I might paint the underside house tone

Keep wood columns and beef them up with covers. The stone columns look out of place unless you can find some simplier ones.

No to the stone columns for sure I would leave as it is built I see no reason to beef up the posts at all. Maybe show us the house and then the question might make sense.At most maybe add to the posts to beef them up but no context as to why.

Is there any stone on your house? If not, then no on stone columns.

On the fat columns, the fussy folderols at the top look odd against the rustic wood of the pergola. Just plain is better.

Yes to beefier columns. But you need ones that match the style of your home and those stone ones do not. Show other pics of the exterior of your home so we can make suggestions.