If I want a higher performance LO Chain, should I consider seperate VCO with discrete PLL instead of integrated PLLVCO? Are ADI still developing VCOs?

Yes we are developing standalone wideband VCOs but most recently a new family of Quad band VCOs that can cover 8.3GHz to 26.6GHz in just 3 IC's. Of course designing with narrow band VCO gives optimal Phase noise and desgning with wideband VCOs means optmised BOM but sacrificing some performance.  So at ADI we developed multiband VCOs with multiple narrow band cores to cover larger RF bandwidths in one IC and give optimal Phase Noise. Externalising the PLL & only using fundamental oscillators which means no sub harmonic tones delivers greatest balance of integration and design flexibility and performance. Our Multiband VCO solutions are great for this. Separating the PLL and VCO ICs allows for best spurious rejection, but of course the design area will become larger. It’s a trade-off and balancing act.