I have a L5300 i7-8665U CPU with Intel UHD Graphics 620 running latest windows 10 

Works fine with one monitor via HDMI on PC and one monitor via VGA port using "port connect professional docking "  (https://www.portdesigns.com/en/418-docking-type-c-travel-1-x-4k-.html) 

But occasionally (and very often during google meet session) PC runs super slow - the evidence points towards the GPU but its not abundantly clear this is the isse - CPU etc are not excessive although Google Meets own performance monitor  shows 100% (not sure if this is a hybrid calculation of CPU GPU memory etc) 

Question 

1 - does using the onboard HDMI port and an external VGA port more more load on the PC than getting a single external device which supports multiple monitors via USB-C 

2 - does it matter that one external monitor is DT ST2320 and one is P2319H 

bith have VGA and HDMI ports would it be better to run them both via HDMI cables ?