OAuth or Personal Access Token for Make - which should I use

Unfortunately, everything is always tied to an individual account.

However, since you are on the Enterprise plan, you can create free service accounts which:

(a) are only used for API access,
(b) won’t cost you any additional money, and
(c) won’t get affected when people leave the organization.

I talk more about these free service accounts in this thread:

The app that you are connecting to would need to provide you with this URL.

For example, for Make.com, the URL is https://www.integromat.com/oauth/cb/airtable3

From what I understand, I believe this means that each oAuth integration can only be used with one external app, whereas a Personal Access Token can be used across multiple apps.