it’s complicated, in short… so, maybe?
long answer is:
LMH (nee Le Mans Hypercar) is replacing the top-flight P1/H-classes, offering manufacturers the possibility to go crazy with tech and/or design (strict rulebook though). iirc, the hybrid-system has to follow a few envelope-parameters that restrict deploying hybrid power and ICE-power, so balancing/managing these two will be paramount for success in this class. You can be ballsy and ditch the hybrid stuff, like Glickenhaus does, or go all in, like Peugeot will…
LMDh (Le Mans Daytona… h. Seriously! h. Over at dailysportscar they christened it LMDhusky, and that’s what i’ve been calling it since then) is based on existing P2-chassis that are getting custom-tailored bodywork for manufacturers that want their prototype to look like their products/design language. It’s basically IMSAs DPi 2.0, really. Tech-wise, they get a spec-hybrid system and iirc a few more limitations in terms of engine choice/drivetrain-combo (Hybrid-system shall not be deployed on front-axle, and afaik is only allowed to recuperate on the rear axle, no exhaust-recuperation allowed like e.g. the 919 Porsche hybrid did).
Porsche and Audi will go down that route, Audi rumored to re-use the Turbo-Inline-4cyl engine from DTM/Class One rules (i. e. SuperGT GT500 engine bolted into a P2-chassis), porsche supposedly opting to develo/tune a spec-engine variant (V8? V6 trubo?)
Third option is grandfathered P1, the Alpine A485, has last season been running as a Rebellion Oreca. Has to be brought down to LMH-Levels, will be very interesting to see whether that works… the car was originally a P2 that was converted to P1, then used as basis for their P2 that has won nearly all there is to win.
LMH is egligible for WEC/Le Mans from 2021 onwards, maybe for IMSA from 2023, wouldn’t count on it though. IMSA wouldn’t want to invite LMH over when they had two years to iron out the niggles whereas their top-class starts from scratch.
LMDh is egligble from 2023 onwards for WEC/Le Mans and IMSA. Sebring Double-header in 2023, if happening, might be the first time we see both on the same track, albeit in two separate races. Since they’d be back-to-back, that’d be as close as it comes to equal running.
Will they be allowed to participate somewhere else? Here’s hoping, really…
And Grandfathered P1? Well, unlikely, but maybe Kolles will be invited to bring their ill-fated paper-mobile back instead of ditching 2021 completely, let’s see.
P2 will live on, although in a de-tuned manner, with spec-engines.
P3 will also continue as-is (maybe bopped further down to increase performance difference to P2s?)
P2/P3 should be set for Asian Le Mans/European LM Series,
if P3 will continue in IMSA after 2021, phew, let’s see what the uptake is after Sebring.