a quick search shows this:
cheapest one: LEXUS LS460 ELECTRIC STEERING RACK 44200-50220 (nipponautospares.com)
twice as much: Buy Genuine Toyota 4420050220 (44200-50220) Link Assy, Power Steering. Prices, fast shipping, weight - Amayama
serious money if it goes wrong
There is VGRS issue with these which dealers normally diganose as steering rack replacement but 1/2 members have mentioned this can be sorted with a software upgrade.