On the other hand though, there are still .org and .net if you are lucky.

I usually just use tld-list.com to find all the domains from a particular keyword and then you can buy one which can be nice (eg: I bought https://mirror.forum this way)

that being said, you can find the registration prices to sometimes be cheap but the renewal prices can be double the .com or more (which is around 8-10$)

For my domain of https://use.expert its renewal is around 40-50$ (4x .com price) but probably worth it as I really love it but I might drop a few domains like mirror.forum as its 20$ just doesn't feel worth it to me and I will just auction it in some forums, not really that sure at the moment

So TLDR: you can find some good names if really need be but the idea generally for these startups is to do something similar to what I am saying and then buy the .com later if/when they have the funds, personally I am not that big of a fan of .com but I do realize that I have more chances of remembering .com's because that's the default expectation of the internet.