Is there a way (just like with adwords) to manage all the Google Analytics accounts of my clients with an MCC account? i haven't been able to find something on the internet that might be a solution... Any help would be much appreciated!
Yes, but you will probably not like the price tag.
If you have a GA 360 account this introduces an additional level of hierarchy called "organization". Via property moving you can add properties from your clients' accounts (or remove them if they do no require your services anymore, but then they lose the benefits of the 360 accounts) and manage them via an extra interface that comes with being the administrator of an organization.
List price is 100k per year for up to 500m hits/month. You might be able to get a discount - as a wise man said, "if they expected you to pay list price they would have a buy now button, not a sales manager" - but it will still be very very expensive.