plan for old to new pages

[devdev]

hi

Id love some thoughts on this one please:

i have to create a new site to replace an old one.

the old site has basically three types of pages:
I) service pages (one per product i.e one for black cars )
II) supplementary service pages - ie one for long black cars, another for fast black cars etc - a fair bit of text duplication here which needs sorting
III) service pages that were optimised to include towns in he title h1 etc - very old school
a lot of duplication text here#

when i look at impressions, clicks and positions in google search console over 16 months - they have quite varying rates of performance which some reasonable impression rates and a handful that have top ten position rates

my question is what criteria should i adopt to select which ones get redirect 301s to equivalent pages on new site and / or get deleted?

Thank you