How to extend videos to a make them longer (not just looping)

So I’m using DaVinci Resolve free to try and make this video longer. I want each scene in between to be longer because no one is busting in 1 minute, but I’m having issues making it look natural along with sounds. Was wondering if anyone has any tips on making videos less than a minute longer like 3-5 minutes (not just looping). I couldn’t find anything online so I figured to ask this community.

Video I want longer:
https://discuss.eroscripts.com/t/bouquetman-lancer-artoria-riding/145445

I did extend something in the past but I think they reused frames so it was easy to make it look natural. The one I want from bouquetman seems to be all unique frames…

what i somewhat did in the past:
https://discuss.eroscripts.com/t/misono-mika-extended-version/156382