Hm, I’m a longtime freelance book editor and have a few thoughts to share. I think one page of editing is not enough to gauge much, and that you should be able to get a sample edit of 10 (double-spaced 12-point) pages from a potential editor. You’ll have a better idea after a complete chapter has been edited, and you should have a contract that allows either you or the editor to opt out cleanly at various stages. Another thought: sometimes authors don’t know what level of edit they need, and a good editor can assess this based on reading a few pages of your ms. and spot-checking the remainder. Also: a lot of book editors (like me) work primarily for publishers rather than for individuals. It’s just easier. I know I’ll get paid, I don’t need to educate publisher clients about the process itself, and they send me regular work, so we get to know each other’s needs and preferences. Lastly, I wouldn’t really expect a newcomer editor to be able to handle a booklength manuscript very well (I was that person once — eek). If it’s someone really new, they should have had good training somewhere imo. Book editing is a technical undertaking. It’s also about knowing what to leave alone. Inexperienced people often tamper with authors’ work unnecessarily. Anyhow, I’d be happy to answer any questions.

Another online editing service is Scribendi, which has over 300 experienced and educated editors. They've been around a long time. With this service, you decide how fast you want the book edited and how extensive the edit should be, then they match you with an editor. You don't ever actually meet the editor, but rather work through their customer service team. Their prices depend on your requested turnaround time and word count. You can get a free quote here.
I'd suggest working through each change so you can learn for next time, rather than just clicking Accept All on the Track Changes version. This will take time, but it's well worth it. I usually accept 80-90% of my editor's changes and the manuscript is improved considerably by the experience. After the line edits are updated, I send the manuscript to a proofreader for the final check before publication.
2. Copyeditors aren’t the last line of defense when it comes to a book’s mistakes. Formatting, which is done after an editor has done their job, can lead to unintended errors being introduced into the text. That’s why it’s important to hire proofreaders to comb through edited text *after* the book has been formatted for print or digital. Proofreaders are your last line of defense—but they’re human too.