Yup, renomat in general is very aggressive, and especially if its your first time using it, you need to be careful. Some previous comments have shared to try on inconspicuous spots first and yes, do try it at somewhere not noticeable (I usually do it on the shoe tongue for my oxfords).
Like you mentioned, yes safer removal will be to use leather cleaners or turpentine products.
Little trick for a safe removal of wax through my own experiments, use a boar hair brush on the shine first, then use neutral wax and coat the parts with wax (don't buff!!), and let the old shine dissolve for about 10-15 minutes, then using a cloth and some light pressure to "scrape" it off. (a little bit of fingernail through the cloth helps for very stubborn wax).
Same thing for renomat, I used to just layer my shines with a lot of renomat and used quite a bit of pressure to remove the shine (a lot of elbow grease and very tiring). But after reading an insta post (forgot the handle), I experimented with brushing the shine (boar hair), layering with one-two coats of renomat, and letting the renomat dissolve the wax for about 10 minutes, before "scrape-ing" away with a cloth. Less elbow grease and I believe safer as well due to less renomat being used.
Ultimately, shoe care is a lot on experimenting and everyone will tell you different things. A shoe shine lesson/workshop will be a good investment (I started experimenting after a workshop with Straits Establishment a couple of months back).
I believe Mason & Smith does shoe shining workshops as well, so do keep a look out for those if you're willing to spend a bit to learn (personally learned a lot for myself)