when you have determined a sequence of RNA corresponding to a desired protien you may construct a DNA template with modification to suit your purpose.
the DNA polymerase used for DNA PCR is originally from a high tempurature tolerant organism, [thermophillic bcterium] and it is possible via searching high and low to find an organism that bears high temperature tolerant rdRNApol
https://www.sciencedirect.com/topics/biochemistry-genetics-a...
and BTW the original inventor of PCR [kary mullis]
was awake AF on LSD when he conceived of this technology while sitting on a park bench.
https://en.wikipedia.org/wiki/Kary_Mullis
i believe the original PCR was performed MANUALLY! with glassware and perfectionist tedium.
https://en.wikipedia.org/wiki/Kary_Mullis#Use_of_hallucinoge...
you may find this to be interesting: