Why yes, I would recommend checking out the group-thread 
Let’s Durtle the Scenic Route 
! It’s just an informal group (anyone can post; ‘joining’ is just ‘in your head’ 
) where we share thoughts, experiences, ideas, and even techniques for doing exactly what you mentioned: staying on a consistently slower pace for the long term, and to avoid burnout.
Basically, probably the most important thing to do, in order to actually take control of the pace of Reviews is to actually slow down the number of Lessons you do on a daily basis. Indeed, it often makes sense to pause doing any new lessons until you get your pace back down to a comfortable, sustainable level again.
And the second most important thing, in order to make consistent progress, is to build up and maintain a habit of doing at least one review session per day. Even if you only end up doing a single review in that session, at least do that session every day, to the best of your abilities. Eventually, this consistency will allow you to overcome any pile of reviews, no matter how big.
That is definitely an option, and if you’re really feeling burnout, it’s definitely an option to seriously consider. While it may seem daunting, many people have reported feeling a lot of relief after doing a reset to a previous level, followed by slowing down overall pace. Learning the lessons the second time around takes a lot less mental energy than the first time. But it depends on the person, so it’s worth weighing the pros and cons for yourself.
[Edited to add: Oh, and a third thing that you may want to consider is going for a Lifetime subscription, so that you no longer have to worry about trying to maximize your ‘value for money’, if that’s something that you worry about. I knew I would worry about that, so I went for lifetime right away. BTW, there’s usually an annual sale on subscriptions around Christmas time, so, basically coming right up. Might be a good time to splurge on lifetime if you can afford it. IMHO, it pays for itself pretty quickly, especially if you know for sure that you’re going to stick with learning Japanese, and also if you know you’re not going to go for ‘full speed’.]
Good luck!