This is from Wizards own website. We should, indeed, have been receiving Kaldheim packs for January rewards.
January 2021 Season Reward
Players will receive their rewards for December 2020 season at the start of the next ranked season (December 31, 12:05 PST/19:05 UTC). You must have played at least one ranked game in the respective format to receive seasonal rewards.
As a general reminder, card styles are a cosmetic option only and does not add any cards to a player’s collection. There is no benefit to acquiring a card style more than once; if you achieve Gold Rank or higher in both Limited and Constructed, you will only receive one copy of the card style.
This is from Wizards own website. We should, indeed, have been receiving Kaldheim packs for January rewards.
January 2021 Season Reward
Players will receive their rewards for December 2020 season at the start of the next ranked season (December 31, 12:05 PST/19:05 UTC). You must have played at least one ranked game in the respective format to receive seasonal rewards.
Bronze: 1 Kaldheim booster pack
Silver: 1 Kaldheim booster pack + 500 gold
Gold: 2 Kaldheim booster packs + 1000 gold + Relic Axe Card Style
Platinum: 3 Kaldheim booster packs + 1000 gold + Throne of Makindi Card Style
Diamond: 4 Kaldheim booster packs + 1000 gold
Mythic: 5 Kaldheim booster packs + 1000 gold
As a general reminder, card styles are a cosmetic option only and does not add any cards to a player’s collection. There is no benefit to acquiring a card style more than once; if you achieve Gold Rank or higher in both Limited and Constructed, you will only receive one copy of the card style.