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The team seems defensively solid for the most part, but your Dragon resist is Kartana so Dragapult clicks Draco hard on your team and just gets a kill. This is definitely an issue. Try to fit in a Fairy type, alongside Diggersby it should work well against Dragapult. Also, your Electric AND Ghost Immunity is a Diggersby. This CAN work, but not with Life Orb.
Change it to a Choice Band set (imo Qatk Bslam Eq Fire Punch), try to fit in a Fairy type and a Stealth Rocker. Stealth Rocks are very good, especially for Diggersby and Galarian Zapdos. As for replacements, I'd say Volcarona can go. It's a matchup fish on a team that would appreciate more consistency, and nothing you have particularly clears the way for Volcarona to sweep. Tornadus can probably also go.
Keep the Slowbro + Diggz core, and Kartana + Gzap alongside them forms an extraordinarily scary offensive core, so if you can fit them all that'd be ideal. Perhaps a Heatran would be good here, since it resists Dragon and sets Stealth Rock.
Try to implement some of these changes (and note that you dont necessarily need a Fairy if you have a good Dragon resist like Heatran) and send me the team again, I'll give it another look.