I'll take these out of order because some are related
I can try, but I doubt that'll work for game where the entire premise is exploring a vast wilderness. I can't exactly limit it to "explore one guys back yard". Best I could do is have it be a one shot dungeon with a hex crawl to find the entrance, but the appeal of each is different.
Don't make the game about exploring the vast wilderness... at first. You need to boil the frog.
Here's what you do. You pitch your one shot "The Tomb of Fu Qu Yu".
Generations ago the Sorcerer-Warlord was said to have risen to power via the blackest of the dark arts - dealing with devils, binding souls into fell artifacts, forcing unlife onto the previously hallowed dead. He had terrorized the region - laying waste to all who resisted him, soaking the earth with the blood of entire lineages for the smallest slights. Before he was put down by a party of great warriors of light, Fu Qu Yu cursed everything that lived in the valley, and swore he would return after a thousand years to take his revenge. His corpse was bound in holy rites and was placed in a tomb that been built by his acolytes who insisted on being entombed with him. The area has been taboo ever since, avoided by all.
But now travellers and traders now report lights in the sky over the location of the tomb. Unnatural sounds wailing through the neglected forest. Lumbering dark shadows stalking them from the trees along the trails. Livestock, and now children and hunters have gone missing, never to return. The local Baron knows this is all superstition feeding itself, but the town elders insist that the curse of Fu Qu Yu has reared its head, the ancient evil has slipped its bonds, and something must be done before they are once again plunged into blood and darkness, and they must be appeased or risk the region falling to rebellion.
And there is your mission: The doubtful Baron has charged you with the mission: under take the long journey to the ancient tomb, investigate the happenings, and dispatch any threat should you find it.
maybe have some pregen characters, or ask people for what they want to play - the world is open enough you should be able to accommodate any background you should want to accommodate.
Then you ease them into wilderness exploration & softskills.
You turn the journey to the tomb into a series of checks - good results give the party advantages where they arrive well rested, if they dumped overland travel skills, they arrive beated, bloody, and exhausted.
Your talky characters, give them a chance to say how they used their soft skills in the last town to get them provisions/intel/etc.
Basically Oregon Trail, Fantasy Speed Run. Don't spend more that 30 minutes of session time getting there - if you have amenable players, sort that shit via Email/Discord/SMS/WhatsApp/Parlr/Carrier Pigeon before everyone even sits to the table.
Then everyone goes and explores the tomb of Fu Qu Yu.
End of the session/end of the megadungeon, thank everyone for coming. Get feedback. If this seemed like something people like, do an interest check for The Black Caverns of Xest Ube. Rinse and repeat on the intro. Keep doing this a couple times, and then start opening up the exploration phase go more choices.
You boil that frog slowly and you'll find your core of dedicated players and you'll have tricked them into a fairly normal campaign inside a year.
You said everyone is having adulting issues, which means they will say "yeah! I want an open world where I can do anything I want! No quests! No rails!" but they will really want is "I want to show up and not think too hard. I want to be told what to do and where to go, but I want to made to feel like it was my choice to do that. I might not want to be rail-roaded but I definitely want to be doing 80mph on the interstate. I don't have the mental energy to have to make too many choices, especially ones that make me really have to think about it".
My concern is/was that RPGs are going the way of board games. I got into board games around 2008 or so when you had a boom in euro games like Pandemic, Catan, Power Grid, and Dominion. By 2016 the novelty had worn off and while I liked board games, more and more people slowly lost interest. The real life pandemic killed what little following remained and my game collection has been gathering dust since.
Gathering dust is what board game collections do.
Which I hate to advocate giving Trannies of the Coast any money, but I just finished doing the Tomb of Annihilation adventure system boardgame with some friends. Its solid.
Everybody says "you missed," because after the first 4 or 5 times you come up with a cool description for a die roll, you are just wasting everybody's time. There are dozens of d20 rolls every night, I can't be bothered to come up with an engaging description for each one.
Yup. I'll add narration when its novel or there's a crit hit/fail, and sometimes sprinkle flavor, but I don't want to have a five minute narrative sequence time someone touches the dice. Especially since we're doing 4e - jesus we'd still be in the first dungeon if we did that.
Just when there is something notable that happens, I try to focus more on how enemy action or the environment has thwarted the players.