Updating to 26.5.2 didn't make a difference for me either. Neither did updating the chipset drivers from 8.02.18.557 to 8.03.25.247.
The issue could be related to what was reported here:
https://forums.ea.com/discussions/battlefield-6-technical-issues-en/performance-issues-x3d-cpu%E2%80%99s/13401879
Though I never monitored monitored individual CPU threads before now and in my case, over all CPU usage is at about 80% with unlocked frames (maybe a little higher than before but I couldn't say for sure), with certain threads going up to 95% at times.
