Ask HN: Good read about productizing engineering consulting services?

I work for a large Civil/Infrastructure Engineering Consulting firm. Our bread and butter is to sell consultant hours to solve our clients' problems. It's a very project based approach. We have recently started investing a lot in building products to turn consulting experience into products (most of them digital). From my observation (I am a intermediate level product manager with domain knowledge), it's really hard to build products. Are there any material out there that I can read?

So far I've found this HBS article a very good start: https://hbr.org/2016/09/putting-products-into-services

This is also a good general advice:

https://www.pragmaticinstitute.com/resources/articles/product/transitioning-from-services-into-product-management/?trk=feed_main-feed-card_feed-article-content

I am looking for more in depth material. Case studies/frameworks/books/articles/blogs...