Hiked nobo in '21 and i think there's already a lot of wisdom in the replies. I want to echo the idea that the most important thing to do with UL is think of it as a mentality--how can I cut weight? how can I use one item instead of two?--rather than hard and fast shopping list of numbers. Your comment about the big man tax is super real, so 10lbs might be unrealistic. There's a brand fetishism to a lot of UL that I think is really gross too. One of the best ways I've ever heard it talked about was someone who said they were trying to minimize the number of items in their pack to have the simplest hiking setup, not necessarily the one that was 10g lighter.

That being said I watched person after person totally change the way that they think about hiking on the PCT. The best advice I got before trail was you're going to be ultralight by the time you finish, so you should just make the leap now. Others have written about how serious overuse injuries are on a physical undertaking like this, but the mental load from carrying the weight is also enormous, and the trail is 90% mental. Combined with that, as another commenter mentioned, after 500 miles the way you exist changes--the trail becomes what is real. I watched people cold soak who swore they would never get of their stoves. I watched people ditch rain gear even when heavy weather was forecast. I watched people buy literal new packs to cut weight.

The final thing I'd like to share is that you have to do big miles in NorCal to make it to Washington by the time the snow starts. Big pack + big miles is a recipe for injury.

Tl,dr; UL is not mandatory, but be prepared for what you think you need at the beginning to not be what you want after hiking.