Question, I want

Question, I want to set up a wp multisite. Plan on having 5 to 7 sites under it which will be mapped to unique domains. Is it better to set it up as a subdirectory or subdomain to do this. I plan on using an ssl on all the new domains as well.

so https://mainsite.com i will add https://mainsite.com/site2 or https://site2.mainsite.com and it will be mapped to https://mainsite2.com and so on for the other 5-6.