If you've ever used sites like https://haveibeenpwned.com/, you probably know that your account information has been exposed in data breaches across different websites.
I've had the same Gmail account since it was still in beta, so naturally, I've used it on a lot of websites over the years — dating all the way back to when I was a kid. As you can imagine, that has resulted in a pretty substantial amount of spam and scam emails over time. This was before a time when we had things like SimpleLogin or Bulc Club to hide your mailbox.
The obvious solution would be to abandon the account completely, but there's way too much sentimental value attached to it, not to mention all the services and automations I've configured on it over the years. Instead, I've been trying to clean it up and keep it as private as possible.
Recently, I started using Protect My Data, and so far, it seems to be doing a pretty good job of removing my personal information from the internet. Interestingly, the username and password side of things isn't really what concerns me. I use unique, randomly generated passwords through a password manager, and I don't even use most of those old accounts or services anymore anyway. What I actually care about is the personal information that's out there — things like my name, address, date of birth, and other identifying information.
Obviously, once your data has made its way onto the internet, you're never going to completely erase it. It's already out there, and there's no guarantee that every copy can be found or removed. But I think there's still value in reducing how much of your personal information is publicly available. At the very least, tools like this can help reduce your attack surface and make it harder for someone to piece together information about you.
Combined with SimpleLogin and a few automations I've set up using Google Apps Script, my Gmail inbox is now cleaner than it has ever been. I regularly reach zero inbox, and I barely get any spam anymore, maybe one every 6 months or something. I don't even get scam calls these days — the ones that do come through are automatically screened and blocked.
Personally, I went with the Pro plan, which comes to $204.03 NZD per year after applying a coupon code. I only plan on using it for a year, so for me, it's more of a one-time cleanup rather than an ongoing expense.
Note that if you own multiple emails, you can add them under the same Protect My Data account.

SneakEmail (as an example of an email aliasing service) was around long before GMail - late nineties if I recall correctly. It used to be free, but I moved off when they started charging.
I've had a Hotmail address since before Microsoft took it over - registered sometime in 1997 I think, so that address has been around for nearly thirty years in constant use, and to my great surprise, almost no spam gets into it, and I never seem to get anything legitimate blocked (hard to be sure about that of course, but its been many years since someone chased me up about an email due to not making it through to me), so I think the issue very much depends on who is looking after your email.
Having said that, when SneakEmail ditched their free offering, I just moved to using my own dedicated domain for aliases, which costs me (now) about $27 a year, and gives me unlimited aliases and more importantly, completely control with essentially no management required.
Having said that, $200 for, as you put it, a one-time cleanup isn't bad value if they actually deliver. How will you assess its effectiveness?