A discrepancy between the usual interpretation of Bell's theorem and a full theory of quantum gravity

**** This question has been modified following the discussion below. ****

Bell’s theorem says, in a nutshell, that “local hidden-variable theories (HVT) cannot exist” (since they contradict QM in Bell experiments, which are agreeing with QM). So only non-local HVT could reproduce all predictions of QM; “non-local” here means: involving superluminal signals/influences, i.e. non-Lorentz-invariant signals violating relativity theory (RT) (this is an explicit conclusion of Bell’s well-known article from 1964; some people nowadays understand “nonlocal” in a softer way, such as “violating Bell inequalities”, but for my question we need to use Bell’s original definition). That is why very few physicists believe in HVs, whether local or nonlocal. Now, it seems to me that there is a significant gap between this standard interpretation of Bell’s theorem and the future construction of a full-blown theory of quantum gravity (F-QG). What I call a full theory of QG (F-QG) is one that can derive both QM and GR (general relativity) from more fundamental variables/properties/equations, so this would be a HVT allowing to explain QM and GR, just as electromagnetism can explain optics, magnetostatics etc as special cases, approximations, limits of a more fundamental theory. (String theory, ST, does not qualify as a F-QG, it seems, as follows from a discussion based on the original version of this question: ST is not a HVT, it assumes QM.)

Now, assuming a F-QG exists (see e.g. Nobel Laureate Gerard ‘t Hooft on this matter: https://iopscience.iop.org/article/10.1088/1742-6596/504/1/012003), it seems to me that the F-QG variables/properties/equations would NOT be nonlocal in Bell’s strong sense (i.e. involving non-Lorentz-invariant, superluminal signals) – they would allow to derive GR, after all. So such a F-QG would be a local HVT. My question: is this reasoning correct?

In sum, if I understand this correctly, there seems to be a discrepancy between the standard interpretation of Bell’s theorem and the research efforts of many theoretical physicists, who believe that a F-QG theory does exist: such a F-QG theory would be a local HVT.

Actually, there are one or two known escape-routes from Bell’s no-go verdict (Bell’s conclusion is based on one or two implicit assumptions, which are not trivial; see e.g. the work by ‘t Hooft, who does believe that the standard interpretation of Bell’s result is mistaken). Thanks in advance !