Depends a lot on your product, your target market(s), number of supported languages, number of employees, and most of all: the risk class of the product.
QMS can be around 15-20k
Study: not necessarily needed if you do not need new evidence. Then you can write a literature review, which is A LOT cheaper
TechDoc: yeah, takes time
CE marking: depends a lot on the notified body. Here's a slightly outdated list and apparently, you can pay anything between 15k€ to 500k€: https://openregulatory.com/notified-bodies/
