In addition to the individual editors listed above, the Reedsy marketplace is full of vetted professional editors for every editing level and genre. They screen their editors and only allow the best of the best to be listed on their website. I'm a BIG fan of them because they have made the process easy for me to find the best book editors, book cover designers, and even writers to help me with my projects. Talk about awesome!
Second, consider getting a critique before you decide whether you need to pay for a full copyedit. I (and probably many other editors) will read your manuscript and write a several-page critique for much less than the cost of a line-by-line edit, and if your mechanical skills are reasonably good, this may be sufficient to help you get it into adequate shape for your publication plans.
Unlike most other basic “proofreading” packages, ours includes copy-editing where needed, light revision, rewriting and improved word choice, as well as a one page summary of some big picture issues that can be improved. If we see something that looks bad, we’ll fix it – but we won’t wrack our brains trying to solve bigger issues like plotting, character motivation, story architecture, etc.
It’s always sensible to follow due diligence in submitting your first draft of your book to an editor by making as fool-proof a copy as possible for you because first, it is your own creation, and secondly, a horrid draft sent your editor can end up frustrating both you and him or her. Make your own corrections to the extent you can, so that will make the job of your editor that much lighter and the end result would be a lot more effective.