CPU LAG

I had the same problem, its your cpu. My specs: Ryzen 5900x, zotac rtx 3060 12gb vram, 32gb ddr4 3200 mhz (2x16gb gskil), asrock b450m mobo, 1tb nvme ssd, 650w psu. Make sure you have your windows power plan set to performance, same with your gpu in the app. Then make a User.cfg file with these lines ONLY, in the notepad app

Thread.ProcessorCount 6 Thread.MaxProcessorCount 6 Thread.MinFreeProcessorCount 0 Thread.JobThreadPriority 0 GstRender.Thread.MaxProcessorCount 12

save the file as “User.cfg” inside your bf6 folder where the executable file is located. Make sure you set to all files an not just text documents right below where you name it. This will isolate the game to half your cpu (dont worry anticheat, ea, steam, and windows will take up plenty of cpu on your back ccd). 
Then install process lasso, set ea anticheat and bf6 to your front ccd under cpu affinity and put them on high priority.  Youll only see them while theyre open. This will make your cpu spikes happen every 5-10 min instead of every 20 seconds. Makes it alot more playable. I have a few more tweaks if you actually do these and want more. It wont be fully resolved until EA fixes whatever latency/cpu scheduling error they are facing. Its everyone with a higher end ryzen its not just you

Also try both xmp profiles. Before the update auto (2133 mhz) worked better for me. Now xmp 2.0 in bios (3200 mhz) works better FOR ME. I think its in the xmp profiles latency that causes issues, not the speed (mhz). EA/Dice/BF6 servers have horrible netcode

Sorry to spam the feed but one last thing, i was using a 5500 in this build and never had one problem. I only got these problems when i upgraded to a 5900x