But if I use just Tor, then my ISP knows that I'm using Tor
Not necessarily, because you can use
bridges. These are Tor relays that aren't publicly known, as with most Tor nodes, so they help you circumvent censorship. Although, completely hiding that information from your ISP is not really possible, because you have to install somehow Tor (by visiting the clearnet), and even if you do this anonymously, nobody can guarantee you bridges aren't honeypots.
You can also download Tor Browser by email message:
Send an email to
gettor@torproject.org. In the body of the mail, write the name of your operating system (such as Windows, macOS, or Linux). GetTor will respond with an email containing links from which you can download Tor Browser, the cryptographic signature (needed for verifying the download), the fingerprint of the key used to make the signature, and the package’s checksum. You may be offered a choice of "32-bit" or "64-bit" software: this depends on the model of the computer you are using; consult documentation about your computer to find out more.
But I guess if you're living in a place where email is heavily censored as well, the next best solution is to try to find a download link for it on IPFS.
Maybe, if some bloke is clever enough to store the download on a blockchain somewhere (probably they already have in one form or another).