This will cause a backend issue where the game will not treat the Ultimate Pack's ownership as owning all Pass Tiers. Among many other things this compounds.

Purchase about $20 USD worth of Battlefield Coins, the game's in-game currency. Any lower amount will also do; we just need enough to get the second Battle Pass tier. 2,200.

EA Play subscribers get a 10% discount on purchases of Battlefield Coins. I cannot confirm if the in-game Battle Pass purchase tiers also receive discounts through EA Play, however.

(Be aware that both the Steam Overlay AND the EA App In-Game Overlay must be enabled for in-game Battlefield Coin purchases to work from the in-game Store.)

Once enough Battlefield Coins are in the account, Use them to go to the in-game Store, and navigate to the Seasonal Battle Pass. Purchase up to Tier 2, the Fast Track tier.

If done correctly, the game should now register internally that the Season Battle Pass is Owned, and prevent you from purchasing any further items from its Store element. (There is a separate section for individual Pass Level tiers, that is not affected by this.)

Now that the game believes you rightfully fully own the prerequisite Battle Pass tiers, it is safe to purchase the Ultimate Pack from the Steam Store page. You may need to do this ASAP after getting the Fast Track pass tier.

This unfortunately means that the total price for Battle Pass tiers is not $20 USD through alternate means, but instead doubled to $40 USD if looking to do it safely.

It at least beats the game thinking you do not own all Battle Pass tiers and partially corrupting profile status within the engine for an entire season and more, possibly also preventing it from loading your profile consistently on startup as well.
—
Also, if not already aware, the star ratings on Guides are entirely affected by cumulative Thumbs Up and Thumbs Down ratings. Favoriting it is nice and all, but the Thumbs Up/Thumbs Down system is something that ought to be considered alongside Favorites, which mainly exist for your own reference so you may find a Guide more easily later.

Guides start to show their cumulative Star ratings when at least 25-30 Thumbs Up/Down Ratings are given to it.