I feel your pain, had my own large backlog to clear pretty recently. It can be a grind - good luck! I do think you can improve on streaks though by having % studied in last 30 days or similar instead.
I’m not the biggest fan of streaks because after a while they become the motivation to keep going rather than the learning itself - doing it just to keep the streak. And a streak will always be lost eventually - so your main motivation transfers to something that will inevitably end. It’s like this guaranteed failure point in future. And if you build up a long streak, when you finally lose it all your motivation is gone because the streak was the motivation == you quit.
Which is why I like % studied in last 30 days instead → firstly you can aim to keep it above 90% rather than aiming at 100%. Life happens, sometimes you’re sick, or your grandma passes away etc and you can’t study - doesn’t matter you’re still winning if you miss a day or two with +90% goal. Also if something big happens (family holiday, stint in hospital etc) and you let it slip completely, it’s always less than a month to get back to a winning state (which is not true when you let your 500 day streak drop - getting it back is soul crushing). And finally it graphs nice - just a little bar graph of the last 30 days with number of reviews or something - really easy to see if you’ve missed a day by the missing bar, but also really motivating to see them all filled.