"Different" is what I would use to describe the experience. You have to learn how the software edits. This applies to all editing software. Once you do that and become comfortable with it, editing will speed up. There is a HUGE learning curve difference between S12 and PS22.
You do use all the tracks when editing, yes? If you do and use transitions, you will not have any problems. Placing clips on tracks above or below (you decide on what you want to do) is what I would suggest.
Watch this TUTORIAL about transitions. It explains "why" this change was done. I didn't have a problem before this "new" way, but have adjusted to the new way.
Create a separate post about the transitions that do not work in reverse. Be specific.
I basically use Overwrite, Insert or Replace when I am editing. I never use Smart. This is all part of getting over the learning curve of the software.
When Avid Studio was released (supposed Liquid replacement... NOT), once I got into the software, I never went back to S15U. I have S9-S15U every version.