Hasbro still can use the franchise for products for "young adult" audiences, for example novels, comics or an animated adaptation in Paramount+.
There is a possible solution suggested by me: a (insert X name here)'s Guide of the Shattered Lands, an update of "Sandstorm" with some pages about the city-sates from the Athasian Tablelands, and others about Amonketh and Kaladesh (settings from Magic: the Gathering), an update of the crunch (PC species and the blighter as a subclass with a special game mechanic of defiler magic). The almost return by a back door should be an option to be considered.
We could study variants of the defiler magic, with different effects, to be used in other campaigns. For example with that defiler magic the vernim and flora survive, but it becomes poisonous, or toxic spores are created in the zone, or in the night the taint by the "shadow" is worse allowing a planar invasion by creatures from the Shadowfell, or infernal outsiders are stronger in those tainted zones enjoing a special bluff.
In my opinion the worst handicap besided the lack of a system for psionic powers in 5Ed is limits of options for PCs with the classes and species. Why not to add dromites, psiforged, shardminds, maenads, xephs and elans? Then or we reboot the setting, or we create a spiritual succesor recycling/reusing the favorite elements from the previous one.
Slavery is something not only happened in the XIX but it is real today in some places in the world, even in our countries, when ilegal inmigrants are catched by criminal groups and sent to forced works...but that doesn't mean it has to be a complete taboo in the TTRPGs. Let's use the good sense. We have to avoid the frivolity.
Maybe my point of view if different because in my society the injuries from the past are different, or these have been enoughly healed. If it is something like this, then your duty is to bury the resentment and to search the reconciliation. To stop the hate and the bigotry we also need to earn mutual trust.
I could understand the risk of the franchise to be manipulated by no-roleplayers and to be used as a symbol or allegory about the fight against the tiranny of the reptilian elite or something like this.