I would describe myself having been that person in my previous role (of six years). Started as dev#2, grew to ~100 people, you grow along with the company, having seen everything, had a hand in making most of it, it'd make anyone an expert.

Eventually it got to the point where our engineering manager would assign maybe 10% of my sprint capacity. 40% of it; I already knew what to work on. Stuff my manager, and the manager's manager, had no clue how to plan for. I was rarely included in product planning because "we need you to focus on the work". Literally none of them seemed to care that they didn't have visibility into what I do. Whatever; I'll just create the tickets myself, basically manage the sprint planning for a team of one (me). That worked well. Actually pretty nice. The other 40% was just Slack. Messages all day. "Ramp up meetings" with new hires. "Hey man can you document this thing" (no one ever reads it) (three months later 'hey man can we meet for two hours to talk about this thing I'm not understanding it') "Can you hop on this customer call in two hours, we need someone to talk about single sign on" (sure man, I'll recite the same script I've used for the last fifty meetings, and that I posted in our internal help database, that your team has somehow spent three years NOT learning)

Oh, I'm missing 10%. That was Overwatch. Maybe more like 30%. Because it turns out, you get to a position like this, and short of a company failure, you're set. I once had a project go maybe 3-4 weeks past when it was planned to be done, partly because I took an impromptu week-long trip in-country with a friend, telling no one. I could have taken PTO. We had unlimited PTO. And not fake-unlimited PTO that no one ever takes; real actual unlimited PTO. But that's a process, gotta fill out a form, tell people, and I was in my "fuck process" phase. Spend an hour a day in meetings from the hotel room hungover with a virtual background, respond to Slack messages as they come through. During a retrospective or something my manager commented that "product really screwed up planning how long this would take". I planned it! I gave the timeline! I screwed it up! Absolutely wild.

> I used to get challenged in some of my decisions, which I always appreciated since I could create better solutions. Nowadays people just accept whatever I say as the best way.

The best days of my role at this company were when we hired on a former senior engineer from Google, of all places. I don't know how we got him or why he joined on, except that he really wanted to try a (no-name, small) startup. It was the first time, ever, that I felt like there'd be someone else with the knowledge and confidence to challenge me. He did. Then he left a year later. Probably for the same reasons I eventually left (if you haven't caught on yet; the management were amazing people; and absolutely horrible managers).

> I worry that by not being challenged I will become complacent.

You don't have to become complacent on the tech. The thing I miss most about this role was; if there was some tech I wanted to play around with, I'd just do it. There was no one to question me. I'd deploy it all the way to production. I'd maintain it; grow it; mold it to whatever the business needed. You learn a lot doing that; probably more than being a cog in the Big Tech machine, though its a "different" but still extremely valuable kind of knowledge. A year later that tech is in job descriptions for the new hires and I'm helping them learn it.

But, what I found myself becoming complacent in was (you guessed it): work ethic. Everything was so easy, and the expectations were so low, that a typical day quickly became... 11 to noon, then an hour lunch, then an hour digesting that lunch, then maybe 2 to 4, then a friend just texted he's at the brewery across the street, lets roll out.

> What can I do to change things?

Leave. Everyone wants to be the smartest person in the room. Actually being the smartest person in the room: sucks. There are two ways to fix it; find a smarter person to bring into the room, or find another room. Hire, or Switch Jobs. Hiring the smartest person in the room is, probably, a predominate focus of someone, somewhere, in your company; as it is in every company, and they've failed. Who can blame them; hiring engineers SUCKS. So, find another room.

I've never made a better decision than leaving that role. In literally the first WEEK of onboarding at my new role, I learned five things about how they architect things, plan work, design systems, that induced the autonomic thought "shit let me write that down, this is fantastic and would work great in {SystemXFromOldCompany}", before having to realize I don't work there anymore lol (not to mention, you know, intellectual property, autonomic and such). When I put in two weeks, the old company offered to beat the offer at the new one by 10% (it was already an... 80% increase in TC). Nah, see ya.

That's the thing. You may be the most capable engineer at that company. You spend long enough in isolation there and you may just start convincing yourself you're god's gift from heaven. This isn't personal: you're not, because no one is. But, you're probably pretty good, and you're at a plateau because there's no diversity of thought in your environment. So, you gotta find it. Ten-x engineers are relative. The creator of homebrew couldn't get a job at google.

The alternate option is to find happiness where you're at (or, similarly; don't go big tech, find somewhere else you can be the smartest person in the room). It doesn't sound like that's a good solution for you, so I present it last, but it really is a fine road. There will always be many people smarter than you, and many people not-smarter. It sucks to be the smartest person in the room; but if you can go on impromptu trips with friends, spend time with your family, explore hobbies; hard to call that a bad hand. Work/life dissociation is actually healthy.