I think these comparisons wildly forget context of the games in question to the point of unintentionally strawmanning.
Mystery Dungeon for example is a 100% different system and game type, since the Dungeon exploration entails resource management, freer use of items, and a completely different turn economy from Dungeon to Dungeon. Legends Arceus introduces changes like the Strong/Agile style and the differing turn system, but at the core the game is still built on small-party Turn-Based Battles. MD Hail being nerfed to "~5 HP every few turns and no auto healing" from "1/16th health every single action" is specifically because of how many more actions a floor of MD takes compared to a Battle in either Pokemon game. MD's stuff like Status and other Weather are incompatible with main series because MD's base gameplay systems and loops are a complete overhaul, where LA is closer to a different take on similar principles., Try comparing several classic Final Fantasy games like 4-9 to a game like 10 and Tactics: 10's differences from the prior games are still similar enough to go from one to the other with the Turn-based system and principles like Character Speed on Turn-Rate, small parties, and Player-to-Enemy stat ratios (think RPGs where Player dealing 3k while enemy deals 800 is considered normal because of things like healing, stat scaling, and tank class options).
Meanwhile, Drowsy, Frostburn, and Accuracy-down Weather are not comparable mechanics to each other for a different reason. Drowsy again affects the turn-economy in a similar way to Paralyze, but arguably less detrimental depending on the Pokemon (Paper Cannons don't care about taking more damage vs a Speed loss), rather than completely robbing Pokemon of turns (an effect strong enough that even official games have Sleep Clause). Frostbite same as a Burn clone vs a "you don't get to do anything" status in Freeze. The status effects have consistent effects that are also not so powerful as to limit their distribution, making them potential strategic options to try inflicting as Burn and Paralyze are. Accuracy down Weather is dedicating a moveslot or such to adding more coinflips to the battle, taking yet more time out oif the battle on misses and player input/strategy out of the outcome without specifically preparing for anti-evasion (as opposed to anti-Status being a lot more generalized). Again, these have completely different design purposes for the game state, and compared to the previous statement, nothing about these are even incompatible with the Main Series mechanics the way a lot of MD stuff is (hell, we have the Accuracy Down Weather already as Fog in Gen 4, limited in appearances though it was)
At this point the attitude towards "Copium" of PLA mechanics in the main games feels almost stubborn or contrarian. PLA is the most compatible battle system with the Mainline that isn't a 100% match, and despite confusing branding, people like Joe Merrick point out very frequently that the Japanese branding puts it in the same category as main line games like Let's Go (which more so changed the capture and encounter system), so it's not even like there's major brand distinction to bar mechanics entering into the equation.
I also noticed Chansey's HP bar seems to kind of jitter on the bigger hits, making it look like it drops in 2 smaller chunks instead of one hit from Drifblim's Shadow Ball (everyone was using a Single Hit move). Besides that, the battles clearly seem to have other mechanics at play, considering the time bar below Chansey's HP and we know they're not working on the same turn-based system as normal battles or past raids. My immediate point of comparison is PoGo raids, where the Pokemon have a Fast Move to spam akin to Auto-Attacks in other action RPGs before filling an action gauge or something for their Strong moves. The two get an icon flash suggesting Chip Damage, but their HP doesn't show any visible movement from it, which almost makes me think it's something inflicted by the damage-anemic Chansey rather than a Status effect that would presumably be percentage based or scale in some manner.
