I'm not sure if this is so unpopular here. Hey! I work in a free public university, that is probably the most different place than a startup (at least form size and the income sources point of view).
Just in case it's useful, this is an old post by patio11 when he transitioned from working in consulting+startup to working in Stripe "I’m Joining Stripe to Work on Atlas" https://www.kalzumeus.com/2016/09/09/im-joining-stripe-to-wo... (HN discussion https://news.ycombinator.com/item?id=12464647 850 points | on Sept 9, 2016 | 330 comments)
[1] Edit: And good luck if you decide to not make the change, too.
To me, the biggest red flag in your post is "I'm starting to feel not so happy with my current route". I had started to feel like my startup ideas had run their course around 3 years in, but I doubled down on a complicated one because I can be hella persistent and kept it going for another 3 years. Big mistake. When your feelings start telling you it's time to throw in the towel, it's time to throw in the towel. I don't regret leaving the security of a big company to play the startup game, but I do regret sticking with it for so long, even when evidence had mounted that the market had turned and there wasn't really an opportunity there.
Fwiw though, the only times I ever considered this was when I was upset at my life at a startup. I'm now happy at another startup. So this is a little of do as I say not as I do. But there's no harm in 2 years of big tech. It might blunt your edge a bit but burnout will do that worse.
What is it about your current route that is leaving you unhappy?
Then 2 years later the pandemic happened - I moved back to my parents' since there was nothing to do in the city anyway. I picked up where I left off with that previous product idea and even consider trying it again. I only started because I thought I would be ready to re-launch it by the end of the year, but that did not work out. I actually started rewriting the product from scratch and with that I came upon a related, but a different idea which I think it could actually have a shot.
Again, underestimating the effort, I spent the entire 2021 working on it 30h/week, living cheap at my parents' only to get a very crude prototype and brutal realization in 2022 that I need at least some good 3,000h more, if not 4,000 to launch it. I decided I need to make some space for my life, but first I've had to change my job / freelancing gig, which worked ok to self-fund myself living low, but does not make sense at all for earning decent salary (decent for the industry) and making some savings to possibly bootstrap future efforts. I took as much work as I could for the first half of this year, so now I can work full-time for a few months on an open source project to boost my resume, then looking to get a full time job in 2023 and I'm out.
As for the product I was working on, I did not write it off completely, I still consider I could have a shot to launch it without major life sacrifices (at least for the most part), but it depends on how much money I would make at the new job (I live in a relatively low cost of living area, aiming to get a job at a richer country), but the launch date would be somewhere in 2026, it just feels like too much - I'm afraid the market may shrink severely in the next 5 - 10 years. I have a new more-long term idea which I think is timeless and does not depend on a particular market as much as that one, so my plan as of now is to work the day job for 5 - 6 years, gather as much savings possible, enjoy life a bit more and then quit and hit hard on that other idea (if it's still relevant). Meanwhile I consider developing a small open source project to fill the void of not owning something, I still plan to do some work in that time and keep sharp.
Having said that, I think it's a big dilemma in general because in the 20s we want to have time to enjoy life, but the 20s are also like the most likely time window when one can plant the seeds to gain financial independence for life. I imagine it will be much harder later, as responsibilities grow, maybe some health problems, maybe having a kid unexpectedly, energy decline. I realize that me saying "I will take a 6 year break" may have the second order consequence of never doing actually doing it. That's why I said I still want to do plenty of work and maybe work on an open source project, to not fall out of the game completely. Nevertheless, I can't neglect some things in my personal life either. I can't help but think that I flushed a big chunk of my 20s in the toilet and I need to fix it asap.