Can Pi 3B+ handle the plugins well?

Hi, I plan to use Pi 3B+, 7" Pi touch screen and Logitech C920x/Pi Camera V2 with Octoprint. Are plugins computationally intensive? Is the Pi 3B+ powerful enough to handle these plugins along with running a 7" touch screen and camera?

It really depends on the plugins themselves how much resources they consume, but a 3B+ should be perfectly fine to handle pretty much anything you're planning to throw at it.

Thanks. I don't know the plugins. Probably I will install things like: Octolapse, OctoPrint-Dashboard, TouchUI, SMS Notifier, some kind of slicer.

I would not recommend using a slicer on the RPi. The choices are limited (and/or old). Newer slicers have a GUI which implies running a desktop on the RPi. Both of these things can be computationally intensive which could cause active printing to "fail" (blobs and artifacts are, for the most part, considered failures).

Thanks. I will do the slicing on my PC and send the file to the printer via Octoprint.

I've started working on a modern day CuraEngine implementation for on-pi slicing, but haven't made too much headway yet. I have been able to get the CuraEngine to compile and slice on the Pi, it's just a matter of getting the right profiles configured and such to work with a plugin.