The NA 5.0l V8, but also NA 4.6 and 5.7 V8 engines are quite certainly the last V8 engines from TMC. 60° V6 with forced induction and electric motors is what is coming next. Anyone believing otherwise, is deluded.
If you like the best engine ever built, you have the Lexus LFA or Ferrari V12, but it is not free. Lexus is no more a Japanese an imitation of German premium.
With forced induction, cylinder count and displacement play a lesser role. With forced induction there is no more advantage of a V8 over V6, and with hybrid tech there is no more advantage of a 90° V6 over a 60° V6. With the end of V8 engines (also by Germans), Lexus skipping force induced V8 engines as too late in the game, and the only high performance non exotic engines remaining being 6 cylinders, Lexus will have the most unique V6 with 60° (as opposed to V8 derived V6 with 90° like VAG, FCA, JLR, GM), without the size disadvantages of I6 (like BMW and Daimler).
Although I would like an I6 turbo diesel in the next Land Cruiser, TMC will have only I4 and V6 engines, NA, FI, and NA and FI with (plug-in) hybrid tech, so as pure BEV tech and probably HFCEV tech if they continue on the side.
I do think might have developed an/some FI V8 engines, but given today's context, they might never be see the light of the day.