If the vines still look good I would leave them. You can always start more and have them ready to replace these since they don't take much room when they are small.

The only thing is, if I don't direct sow, I don't think I can keep them alive in this heat. Somehow, it seems that seedlings are more likely to survive the heat if they are born in the heat, instead of having to survive the trauma of being transplanted.
I sure wish I had a garden that was about an acre in size. Squash and melons take so much room and I really love them. One day soon, I'll be moving, and then I'll have the joy of starting a new, giant garden, getting all that real dirt whipped into shape.
I'm actually really glad I'm not in OK, sharing you're miserable weather this year, though. We've had our share of heat, but it's just normal for us, and hasn't been combined with hail, wind, freezes and other bad stuff. Y'all have had a worse than normal year, it seems.
Makes me wonder I'd I should start looking in the Ozarks or somewhere a little milder? Nah, I'd miss all the excitement!

Are the plants still making flower though? Like you I have giant healthy looking zucs but they have slowed down,
The canopy of the zucs was so thick that flowers were complety sealed off. I took of a few stratigic leaves to allow bee access. Hope it works.

Squash are very sneaky things, even the snow white patty pans. You get in there and really root around and there is one the size of a dinner plate growing up on it's side trying to hide.

They are making male flowers but not female flowers. I've been digging in the canopy and occasionally find one but not too often. The kabocha are really sneaky, though.
Yanked the melons, except for ananas. I think I migh throw some melon seeds down in the partially filled lasagna bed. It needs some water to start cooking, anyway. This will incentivize me to water it.