Different page layouts handling in CMS in Drupal 8

I have to create almost 10 pages which have different page layouts i.e one has 2 column, another 3 columns, another 24%/75%/25% and so on. Few have side bars and few don’t. Few also have js effects applied and few don’t. All pages are unique in structure and not uniform.

My question is…..

by using a custom theme how can I create and manage those pages?

BTW I have used Design Studio module but it doesn’t cover all mentioned above.

Not sure if I create my own template file for each node / page and manage?

What are the best practices I should follow to achieve this?

Many thanks

Drupal version: 

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