Bunpro is powerful, but a bit hardcore if it’s your first/only resource. It’s very heavy on fairly technical grammar explanations which isn’t for everyone. For me I much prefer learning grammar by reading the example sentences and their translations.
I’d recommend picking up a beginner grammar book (e.g. Genki) and following that. Additionally although the default number of new grammar points is 3 a day, this is very fast.
Additionally Bunpro benefits a lot from having a good foundation on vocabulary and kanji. On the Web version there is a feature to help you learn all the required vocabulary for a given grammar point.
One more thing - Bunpro has a lot of settings. You can customise how harsh the SRS is, whether you get ghosts, how much hints you want, and much more. It’s worth exploring them every now and then and figuring out what clicks for you.
To answer the question on politeness: Japanese has essentially 3 main politeness levels. Standard, which is what the dictionary will show. This is used around close acquaintances, friends and family. Polite (です/ます) form which is used in essentially all public settings for people you are not close with. Then there’s honourific or Keigo which is used typically in business settings. Bunpro will ask you to conjugate verbs differently based on the politeness level which is usually stated as ‘standard’ or ‘polite’ in the grey hints.
I’ve just checked the explanations for だ and です and I think the distinction between polite speech and standard could be made clearer because it’s so fundamental to the language.
I’ve been learning Japanese for 8 years, and I benefited a lot from a tutor, so take this as a mere suggestion, but try setting the mode to Reading. (This is in the deck settings.) This will make it a flashcard where the aim is to correctly translate the sentence. I think this is more approachable because you don’t have to worry about conjugating the grammar immediately. Then once you’re comfortable with the reading for all the N5 cards, reset the progress use the Cloze Fill-In. This is essentially how I’ve learned the grammar and I’m in the process of doing the Cloze Fill-In.