Here’s an idea. If you like BP most, then instead of using BP to supplement Genki, maybe you could use Genki to supplement BP?
So, try out the Genki I deck. Use the one that includes both grammar and vocab. Also, use the same edition as your actual Genki edition. Make it as your primary deck. Or, if you prefer, make it secondary and use something else as primary, maybe N5 grammar (or else make N5 grammar secondary and Genki primary).
Then, study some of the items from the Genki deck using Bunpro. Say, for instance, study all the items from the first chapter. Once you get them to a familiar/comfortable level, say just beyond the Beginner SRS levels, then try studying the Genki chapter again. It should be much easier to study by that point, since you’ll already be familiar with the material.
This could get you a head-start on studying the Genki book!
I would caution, however, that it’s possible that doing things in this order might make the Genki book ‘boring’ to read, like, “Eh. I’ve already covered this stuff in Bunpro. Do I really need to do the exercises?”
When I studied Genki I, I actually did find doing the exercises worthwhile because it exercised my language muscles in ways that SRS alone (even the great Bunpro) didn’t really exercise. Then, I used Bunpro’s Genki path to reinforce those exercises by keeping them on a constant SRS ‘loop’, until I became fully proficient with them, and they advanced ahead as things do in SRS.
I believe that if I had done Bunpro first, it probably would have taken me longer, overall, to learn the same amount of grammar, and I probably would not have appreciated the exercises as much – and thus, I feel, I wouldn’t have actually learned as much from them. But that’s just my personal belief based on my own experience and my own personality. Maybe things work different for other folks.
So, I’ll just say that since you already have Genki I, then might as well try to put it to use, right? If it takes using Bunpro first, to do that, or maybe just to get you started on Genki, then I don’t think there’d be any harm in that.
My main point, though, is that using Bunpro and a textbook at the same time is a pretty darn good way of progressing, IMHO. Better, IMO, than using one or the other separately. Might be worth trying out for yourself. (Indeed, originally, that was one of the main selling points of Bunpro when they first started, was this integration with existing grammar resources/textbooks.)