R7 eye AF random disengagement/jumping all around and poor acquisition

Is anyone else finding that when using eye AF, there is a lot of random AF jumping between subject and the surrounding, even when when using Spot AF? I have subject tracking deactivated in the AF menu 1. I am still seeing random AED disengagement where it is at first clearly locked onto the eye and then for no apparent reason, it jumps to grasses or nearby branches. This is especially true when even static birds are perched in front of a busy background.

I've played with both AF "Auto" case as well as Case 2 - setting tracking sensitivity to -2 (locked on) and accel/decel to +2 without much difference.

The only way I can keep the focus point more "sticky" is to not use eye detection and just use regular af in cases of busier backgrounds/further subjects. But I could do that just as well with my old 7Dii.

Any advice? What am I doing wrong? Is it just a limitation of a $1500 camera (vs something like the r3 which will literally lock on and hold focus on a tiny song bird hiding behind branches in low light)?

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Second observation I am disappointed by is the eye AF acquisition struggle in the first place. Especially when the frame is busy with branches, etc. On my old 7Dii, I could point the central spot AF through a bunch of foliage onto a bird, press af, and it would 99% of the time immediately AF on the bird. On the R7, even using the spot af pointed directly onto the subject, it will randomly focus on a nearby small twig that's 40feet in front of my subject.

I am finding that I have to do A LOT more of manual "pre-focus" by hand to get close to the focal place of the subject, and only then will the AF latch onto subject. And even then, it's not very reliable - it will often immediately jump back to something that's way out of the subject's focal plane and I constantly have to manually bring it back to the subject. Any advise? This is on R7, ef-rf adaptor, 100-400ii lens.