While I do agree the Ultimate Booster needs to be addressed soon, I would ask you to stay your frustration a bit longer. Based on JP's history the Ultimate Boosters addition should be soon.
JP April 24th 2019 Ep6 Releases, May 29th 2019 armada arrives, August 21 2019 ultimate boosters added to Photon booster exchange.
I'd like to note the JP Cleasis units weren't available unit July 2019 vs (Global's ep5 release), & Schvelle units weren't seen until October when they released UH Dragon & ep6 ch3.
Going on, the date the Ultimate boosters came into play was about a month after they were started dropping from ultimate bosses (July2019) vs (Global had Ultimate boosters drop in Ultimate Quest in EP3), the day the Ultimate boosters were added to the PB exchange (August 21 2019) was also when JP first had access to dismantle 14&15 stars weapons & wouldn't see Rivalate(リバレイト) until December.
Though for JP, the Novel were only available through a limited exchange & wouldn't have a free access exchange to them until a month later.
I Assure you they are coming soon, probably with a new UH variant quest on the horizon. While I realize the small time frame may only harden your case, however it would be more months for JP to receive the rest of the UH fields where as Global got them all upfront on EP6 launch along side all the weapons from every JP crest exchange (though divided between rising 5 & Unique badge) . So all things considered give Sega a bit more time.