Your test is showing high lag before you connect to Blizzard’s routing partners or servers. The game client update will have no effect on your home network and ISP nodes close to you. Have you contacted the ISP?
This is probably the issue. Mobile broadband doesn’t meet the system requirements for Overwatch because of its unreliable nature. Things like weather, network saturation, and priority connections can cause service interruptions.
I’ve called my Internet provider, did a factory reset on the modem, replaced the modem prior to this and changed my wireless adapter as well. It’s on 2.4 GHz and the issue is still there. Hardware is definitely not the issue here.
Your previous test showed over a 2 second delay (2494ms) between the PC and modem.
I’m guessing you’re playing on either Los Angeles or Chicago servers periodically, and after playing on them all night, I must report that there has been zero lag. So that tells me this is either something local, or something on your particular route to Blizzard. You could try a VPN to see if changing your route improves the lag, but you’ll need to select and set that up on your own.