You certainly can upgrade the machine to an i7 CPU of the same generation.  If current CPU is i5-7400, you can upgrade it to i7-7700.
One of our desktop PCs (Inspiron 3668) runs on an i5-7400 CPU @ 3.0GHz and we have been having issued with video conferences glitching (mostly zoom).   We have updated the RAM in this machine to 16GB and our internet speed at the PC is 500+MPS.  The graphics card is an intel HD650.   Anyone have any experience with this?  Is the CPU too slow or graphics card too slow?   Can either of them be changed on the Inspiron 3668 unit?   
Can I change an Inspiron 3668 desktop PC processor from an i5 to an i7 or 
higher?