trimming video in preview

Just have a question about trimming a video in the preview.

I have a bunch of drone footage, some are too long or have several useable parts in it.

I was thinking to trim the useable parts in the preview.

When we trim the portions we need, does it affect the videoquality, framerate, codec, ...

Does it really keep all data minus the portions we don't need.

I would like to keep maximum quality through my whole workflow.