Isabella Transit sun canopy (poles)

If all else fails then it could be worth seeing if you can find a dealer who keeps a tumble bin of salvaged awning poles, for those seeking spares.

Delve into that for suitable lengths & size IXL or carbon Isabella poles from which you can cut the requisite tubes for your needs, ignoring what end fitting they may or may not come with.

All the end "bits" needed are likely to be on an accessory rack, Isabella cover spares for most things.

I got a much cheaper extra veranda pole this way. I used the Nutbourne Chichester Caravans, albeit many years back.