Here’s a link to the federal lands and indian reservations within California.
https://nationalmap.gov/small_scale/printable/images/pdf/fedlands/CA.pdf
None of the federal lands will be part of any secession. I have no idea of the BIA has any say in what the tribes can or cannot do vis a vis joining a secession movement or not.
California is not going anywhere. Kick the illegals out, permit the citizens to exercise their state’s right to the fullest, and enforce federal law consistent with the ninth and tenth amendments. Practically speaking, California is way too strategic, too wealthy, and in all other ways too important to permit secession. Won’t happen.