Anyone else struggle with recovery doing bells vs typical bro split workout?

What gives!? I am 48 yo male. I can go to my gym and do a 45 minute all out strength bro split workout using machines and free weights. Including warmup sets, and 4 sets to failure for 4 or 5 exercises using relativley heavy weight. I can go 4 days a week and progress, grow and recover just fine. Ive done so for 10 months.

For intel my recent working weights have been: curl 80lb bar, full stack pushdowns, deadlift 300, squat 260. 4 sets.

However, I have recently switched to doing a full body double bell kb home workout 2 days per week for 45 minutes instead and it puts me in the weeds. Like i need a nap immediately and I am tired to my bones for days. I do sets of swings, cleans, squats, presses, and carries. Im not followimg a specific program. Figured I would just get accliamted first. I use teo 16 kg bells for warmup sets then two 20 kg bells for working sets. Also a 24 kg bell for suitcase carries.

The only other time I have experienced similar fatigue issues was doing Starting Strength and after a while my cns was super taxed. That was 13 months ago.

Anyhow, all other controls are the same. I know how to eat, sleep, active rest. No added stress or stimulas. I just dont get it. I have been doing the kb routine now for 3.5 weeks and its been a mind f*ck.

Is it simply the change in stimulus and my body needs to adapt? Or?