Do you not have a bar to work with? For squats and deadlift, a bar would allow you to simply move much more weight, and in effect, get a lot stronger. DB’s being used for these movements are not the best option, very cumbersome and just won’t allow you to use the max amount of weight possible.
“More functional” is a term people throw around more often than not. I think squatting and deadlifting with a bar is far more functional and effective than using DBs for these movements. Upperbody work is different and DBs are a great way to stimulate strength instead of using a bar. But, I don’t seee how doing a movement where you’re going to have trouble holding the weight (squats mainly) will positively impact your strength if you can’t use the max amount.
I’ve been squatting for years (almost 8 yeasr) and I think that even now, using DBs would just be problematic and my squat would be no where close to where it is now. There’s functional and then there’s going overboard with the term.
I’m not trying to put you down, just saying that there’s a lot of BS floating around about strength gaining and the bottom line is think what is the best way to lift the most weight that’ll transfer over to what sport you do.
I’d comment about the rest of the routine, but I think if you’re going to take my advice (not telling you too, just offering), then the routine might change a little.
I hope this helps.