You’re posting in a user community with other Apple users and not with Apple, and a community about a Mac screen-sharing package for sites with lots and lots of Macs. This package and this community are not particularly related to keylogging nor loss of passwords or vendors that get themselves breached and expose trusted information. Not the best spot for security information.
If Keychain passwords are getting changed and if you’ve wiped and reinstalled macOS, then your local password or your Apple ID password (or security questions) or one of your reset email account passwords has probably been compromised. There are other means of ingress, though those are either more involved, or require local and direct access to your Mac hardware.
If your chosen service providers are using trivially available information as authentication, then your choices are to contact them and discourage them for that and to contact your governmental representatives about security, and potentially to select different and preferably more secure providers, or—in some cases—to provide deliberately false information to the providers that are soliciting the information electronically for authentication. If they ask for your motherks maiden name, provide some other relative’s or friend’s name, or use what amounts to a password. This lattermost case works well for services using web forms that prompt you for reset-related authentication questions. This approach doesn’t work so well if you’re forgetful.
If it’s your passwords that are being breached, that’s usually due to password reuse, or due ro passwords that have been exposed to other folks, or (when some service you’ve subscribed gets breached themselves, and sometimes both. Or passwords which are nit sufficiently complex. In the case of macOS and iOS, the password generators and Keychain work together very well for this; for picking secure and unique passwords. There are third-party add-on password managers that can work well for this task too, and with a variety of platforms.
Enable two-factor authentication on your Apple ID, and other key accounts and online services that implement that.
Don’t click on links in mail, be extremely skeptical about messages and particularly mail attachments, and don’t believe any mail is actually from the user that’s displayed. Mail is easily spoofed, and spoofed mail is one of the more common ways that folks are getting breached. Send folks a scary YOUR APPLE ID HAS BEEN BREACHED AND IS LOCKED! LOG INTO OUR (convincing fake) PORTAL AND GIVE US YOUR CREDS mail messages and ilk are quite common.
Troy Hunt’s haveibeenpwned.com site can show if your email address has been in a known breach. Never reuse that password, if so. (There are scams here, sending folks breadhed passwords as part of extortion scams, too.)
As for these ongoing breaches, contact the local police and/or your preferred legal representation for legal advice.
Again, Apple Remote Desktop can’t get you in trouble, unless you’re already in trouble with an exposed password or some other vulnerability. If they’re able to connect and use a screen-sharing package, your security is already toast.
I really should extend this reply and turn this into a user tip. Ah, well. Maybe another day.