Transfer non-conflicting files first

Instead of showing a window with a question on what to do with conflicting files, which blocks copying until user chooses an option

it would be nice to process all non-conflicting files and ask user about conflicting ones in a separate window, which would not block the copying process.

Thanks for your suggestion.
Unfortunately, that would be a huge change.

Ok, maybe then

1. find conflicts first
2. copy all non-conflicting files
3. ask user about conflicts

?

That's what synchronization does, isn't it?.
https://winscp.net/eng/docs/task_synchronize_full