can i use Webproxy and LoadBalance same time?

i can use Webproxy and LodBalance same time?

in virsion 2.9.27 i try butt not working both as same time!
i have now 3.22 with 2 WAN with LoadBalance, is working fine! can i use Webproxy also same time? and extarnal proxy server if i want?

what kind of load balancing do you use ?