snip about 7 stars Tera raids
Premise: I don't think the 7 star raids are "perfect", however I do disagree that they are designed poorly.
I also 100% agree there should be some easier way to access Tera shards, but I'm also quite confident this will come with DLCs eventually, kinda like Gmax shrooms and Ability Patches eventually came in SwSh, since the progressive introduction of QoL seems to be one of the key features of the DLC format.
I think your problem is your approach to them. You said you wanted to use your Arboliva but had wrong Tera type and thus changing it would be a chore.
I had same problem, incidentally... and so I just went, caught a few random Smoliv until I got one with Grass tera type, and just leveled it to 100 with the plethora of XP candies I stacked up by now, then bottle capped it up. Didn't even bother EVing it. I don't see any reason to "change" my competitively trained Arboliva for the raids, I rather have dedicated mons for them (I do have a Vaporeon and Qwilfish specifically geared and evd for previous raids for example).
I do like the design behind these raids: I consider them puzzles (I am still somewhat sure this was official words, but I can't find the source anymore, so consider it my thought instead), where you're required to find the solution to. In this case, the solution was "somewhat bulky grass type OR ground water absorber which can either setup and live long enough to Terastal, or provide support for someone else to do that".
I like the fact these raids force you to think out of the box on how to beat them, compared to "ha ha supereffective go brrrr" that is basically the gameplan for everything in pokemon games, and they even encourage support moveset that can single handedly carry a team (Clodsire and Gastrodon support sets with Mud-Slap for this raid can do absolute miracles and if Tera Grass can even carry them, as well as support Arboliva and Toedscruel with screens and Sun).
There is one major flaw in the raids though, which isnt just 7 stars, but honestly all of them, just way more evident in 7 stars: the fact you get punished for other people's mistakes.
I get that they want people to cooperate for them, and find solutions toghether, nothing wrong with it, but considering the insane amount of "super casuals" that play them, as well as well actual kids, I think they need a different option than "every death punishes the entire group".
As shown in other games (expecially World of Warcraft mythic+ system recently, but not limited to it), any environment in which the entire group gets punished for the failure of a single person leads to toxic environments where a "meta" is created and people who play outside the meta are often isolated.
We've all seen during latest raids how most raid creators will drop the lobby as soon as a suspect mon is locked in, or people drop off as soon as someone locks in a non-widely aknowledged viable pokemon. Heck I've been doing it myself and I hate it because I can't be arsed wasting 5-6 mins in the already somewhat buggy raid interface knowing that we aren't going to win cause the genius who locked Miraidon will both just die and buff Pikachu with lightning rod.
I would really hope that GF changes their design on this kind of challenges by changing the way death penalties work, in order to just punish the player and not the team. Tera raids would be *massively* less frustrating if instead of a global timer reduction, a player's death would just cumulatively increase their respawn timer, that way the single person who locks a terrible pokemon will be punished either ways by increasing death timer, but the rest of the team isn't. NPCs deaths don't punish you based on same concept (you have no control on what they do or what they bring), so I don't see why other players' deaths should.
I already play enough League of Legends for my daily toxicity dose, I'd rather not have the very same kind of mechanics in my children game thank you.