Before I get into any lengthy discussion here: I agreed with Kim and I don't think what I wrote warrants a separate answer.
In essence, it's a play on Kim's suggestion, as series production is mass production is "The manufacture of goods in large quantities, often using
standardized designs and assembly-line techniques."
https://www.thefreedictionary.com/Series productionOften, "Serien-" in German is not translated into English using "series" (serial is best reserved for number, killer and adulterer). It's just mass production, commercialization, etc. We've had a Q about this (re cars):
https://wiki.proz.com/kudoz/german_to_english/electronics_el...In the auto industry, series is indeed common. If it were another sector, other options (as suggested there) may be more appropriate.
I only wanted to draw attention to the fact that a) you could avoid the issue altogether by using "standardised" and b) that it should be -s- instead of -z- and bespoke instead of custom in BrE (cf "custom" entry in Cambridge, Oxford and Longman).
Best