YSK there are sites that offer you a temporary email address for signing up for services that require one (like some Lemmy servers)
They work by giving you a random email address that is available for a short time (ex. 10min) and an inbox for any messages you recieve during that time (ex. an email verification message from a Lemmy server)
I didn't want to recommend a specific one, however Googling "temporary email" should give you several options to choose from.
Also be aware that sometimes the decision to reset the password is not done on your side. Sometimes due to attacks or similar website owners might decide a forced reset and that might require the email.
I had a scare when i went to setup 2fa, I guess i only copied the last digits of the link thinking all I needed were the numbers and then I couldnt sign in, luckily I still had an open tab with my account signed in and was able to redo the 2fa before being completely signed out, with no email on the account I would have had to start over
You would be surprised.  I work at a IT helpdesk at a university and I think 90% of all students don't know what password manager is. Many have them "stored" in the notes in the smartphone.
Many people don't like putting their eggs in one basket. Which I get. But imo as long as you're properly securing everything as well as you can, most decent passwords managers are trustworthy enough.
I'm personally deeply skeptical, even if it's from one of the most secure companies I would have a heart attack if I hear it's hacked.
I personally just use pen and paper, two copies, and try to do variations or new passwords for things I care about and then one common password for useless things with no credit card info.
There are also more permanent alias services including Firefox Relay, SimpleLogin, AnonAddy, and DuckDuckGo. You can turn off each alias that you no longer need afterward.
I’ve also seen people use temporary emails, forget the password or just need some sort of comms and then lose their account forever to the dustbin of time. These things happen.
https://simplelogin.io/ - they're now owned by Protonmail, I think, and the service is still great. I have hundreds of alias e-mails with them on a custom domain and they're as permanent as you want them to be. You can also use their domains to be more anonymous if you want.
I prefer Apple Relay through my iPhone, it creates an alias that gets redirected to my inbox. if I see it gets spammed, I can in any moment delete that address. and bonus, they will never have my email account, so they can’t trace me, if there’s a leak the leakers won’t know my email, usernames etc.
Proton Mail has aliases that you can generate and then disable until you need it again. They are also integrated with simple login but I haven't tried that out yet. I pay for unlimited so I have enough aliases (for now). I've even started creating ones specifically for my utilities like power, water, electricity, cable, etc.
To sign up for eBay. Now you can filter all of the garbage sent to that address easily! Bonus, you get to see who's selling your data which is always frustrating and entertaining.