How to export videos with best quality? (Resolution & Bitrate changes of videos)

Hi friends!

I was wondering how you can export your videos so that you have the best quality?

For most videos i only have the option to export it in Full HD (1080x1920), some of the videos i can export with a higher quality of 2560x1440.

I don't really get on what it depends on. Also the export Bitrate changes from video to video and i really don't get on what it depends on.

I mostly shoot with the same setting for videos, which is 5.7K/30fps (with 360 mod).

Somebody knows on what it depends on to have different export options?

How can i always export with the highest resolution and bitrate?

I appreciate your answers.

Thanks & cheers!

Stay save! :)