Forza, by your definition, is photorealistic
I've drawn the line at anything in previous Forza gameplay footage I'm afraid, it just isn't during any gameplay that I've seen, regardless of lighting. But maybe future updates or cloud gaming/computing options could render it all perfectly ray-traced and touch up any poor textures/vegetation/barrier and crowd issues our eyes might pick up on when we slow down - maybe AI could do this for all old games. I haven't seen anyone ever seriously suggest Forza is photorealistic, except now in recent marketing of the unreleased game that we need to wait on and see much more of to judge if their claims hold any truth.
The 1080p point is one I'd sort of agree with, for Xbox's main YouTube account to generally still solely feature 1080p baffles me, but maybe they need to for Series S players?
Obviously non-HDR TV shows still look good at 576p and 720p retaining their full photorealism since they are indeed video of real world events though, so the resolution push is almost marketing nonsense in the same way as megapixel counts on camera phones can be. Maybe FM8 need to wait on AMD finalising FSR 3.0 for release and it'll be there in a decent upscale. I hope so, or just for something close to those GT7 replays - especially given they've already shown better vegetation in FM8, as GT7s grass is one of those areas the eyes pick up on not looking too real in the ray traced scenes.
On the 'film grain' type front I felt Motorstorm's beta was heavy on things floating in the air even when trees weren't swaying and wondered if that could be a reason? Again not photorealistic but up there with FH5 in some parts, lower in others. Quite hard to judge tropical settings as I've only been to Cancun in Mexico which had real nice really light sand from the coral but maybe not too much like either of the games. Vegetation wise nothing like FH5 or the different again from the WRC9 stages where smashing through cactus when I lost control made me think of Forza. Crete in Greece has a really tropical look with real clear picture perfect water and little boats - be a nice game setting, and on my honeymoon was lucky enough to visit tropical Zanibar island after Kenya (it's rally locations in both game stages and real footage still somehow looked a bit different to where I was but wouldn't have been too far away) where the roads can be an experience - it surprised me to have looked like Scotland in places I was expecting more desert like from watching too much wildlife on BBC - it'd be a great setting for some films or TV series with more depth. I guess time of year can affect foliage quite a lot so must make life hard for developers, especially if seasons start becoming the norm.
For other games these Ride 4/5 UE4/5 comparisons are a bit concerning so far, but it'll be good to compare FM8's Le Mans with it's upcoming Le Mans Ultimate release to see what else should be in the pipeline from Motorsport Games. AC2 maybe waiting until FM8 releases before showing us anything?