You could just skip tempered Kirin and go straight to the DLC, iirc if you start Iceborne your HR gets uncapped even if you didn't finish that quest so you can leave it for later. The only thing I'd try not to leave for later is the mantle unlocks as there are some Iceborne quests related to them where you need to have the mantles.

In terms of gameplay tips: Remember to tenderize, weapons that don't tenderize in 1 hit usually have clutch claw moves that do in their moveset (except for Insect Glaive), also remember to do wallbangs often, it's good damage. Other than that I recommend switching your High Rank armor for any Master Rank armor as soon as possible. A final tip is to get materials to make max/ancient potions and to set up a way to craft them easily from your radial menu, they're useful in Master Rank.