Edit from internal or external SSD MacBook Pro 2018

Yesterday I bought the base model 15" MacBook Pro with 256gb of storage. I did a quick edit today and so far it is a great computer. Usually I work on one project and after I finished the project I transfer the files to a 2tb external hard drive. But after two days with the new MacBook, I only have 150gb left. This is only the OS, Adobe programs and the media files of one project. I am now thinking of either:

1: I return my Mac and get one with more storage (512gb). But storage at Apple is really expensive and 512gb is getting full quickly too.

OR

2. Get an external SSD, for example a 1tb Samsung T5, and edit larger projects from the external ssd. This is a cheaper solution and I read online that it is not a problem to use an external hard drive to edit from. But on the other hand, the Internal SSD of my Mac is very very fast. I also like this solution, since it keeps my Mac clean.

Do I notice any speed difference with an external ssd compared to the internal Mac SSD? What would you do?