Sudden Lag Spikes

I am having sudden Lag Spikes that kick me off my game and lag all other devices. This has been happening for over a month.

I have a new router from Comcast.

Resetting does not help.

Any customer service rep does not help. Or the signals they send.

The tech that came by did not provide lasting help, although he was helpful.

A VPN does not help.

Reinstalling my driver's does not help.

Opening ports does not help.

Moving the router does not help.

Beamforming does not help.

Splitting my wifi bands and only having my PC on the 5.0 network does not help.

I pay for a 1200mbps plan and only get (via Xfinity app) only 50% of my plan, even though the tech said I have a good node connection.

I am at my wits end and am about to cancel my Xfinity plan if this cannot be solved.

I pay way too much for this plan to have these issues.

I do a lot of streaming and gaming, and cannot afford this unreliable service.

Is there any insight on this topic?

Edit: I am getting temp bans from a game I stream and this is a huge problem for me and my friends/followers.