I would buy all the accessories and then wait for the new mainframe
Ditto. Get the the bags you want on sale, then, unless you're married to the load shelf thingy or just really like the discounted price on the F1, get the new frame or similar.
I've got the F1 mainframe currently and it works great for me without complaint - like any gear YMMV of course. I don't have a lot of use for the Vapor series bags not needing a bunch of compartments/etc. and just use the zip on dry bag for hauling camp paired with batwing(s) to use for hunting/day use. Last year, all hunting season, I just used one (single) of the new big batwings and that was it - plenty of room for everything for a day hunt including puffy jacket, puffy blanket, rain poncho, game bags/kill kit, food, hydration, plus usually a spotter lashed on and my rifle via a Slik Sling.
Sooo, I have the 4000c dry bag, two of the Gen1 batwings, and one of the new large batwings for larger items and swapping around as needs and various outings arise. Always attached to the frame/belt I have the small general purpose pouch on left hip, the "double threat pouch" on right hip (as a quik catch all for gloves, headlamps, garbage, etc), and the sustainment pouch molle'd to the frame containing hydration bladder, emergency kit, and half dozen gate-keeper straps.
A single large batwing is perfect size daybag for me - single large batwing containing day gear with mule deer hind/front/backstrap/tendy:
It would be the rare pack that didn't take a little bit of "personalization" to fit/feel best and I have mod'd mine over the years to now I have the K4 belt that I have rigged to make the whole frame ride slightly higher on my back and the longer padded shoulder straps. I've been swapping between 45# and 60# sandbag rucks since about March and feels great.
My plan is to pick up the new frame when available, or similar, just because I don't like the load shelf thing - it really doesn't serve much purpose and kind of gets in the way. I'll keep the F1 set up for training/rucking and the new frame dedicated for hunting/backpack stuff.