One thing to consider, X950G 85" and Z9G 85" have X-Wide Angle technology which inhibits contrast. How long Sony plans to offer this disadvantage (IMO) is unknown.
FWIW X900F 85" has no wide angle, and offers better contrast than X950G. However, it does not have the Ultimate Processor and eARC, if that's important.
With your current TV, you may or may not see PQ improvement with a jump to the five-figure Z9G. You would not see PQ improvement with jumps to X900F and X950G.
Good luck, have fun.