I use the whole Proton suite! That way I only need to memorize one very strong password, (well, OK, two, but the second one is a small modification of my phone unlock password to get out of BFU mode) as I use 2 password mode with 2FA with TOTP in between the two passwords! So I use Authy to hold my TOTPs, and ProtonPass to also hold all my logins and TOTPs.
That way, since I also use TOTP on Google, along with a 21 character pseudorandom passphrase with letters uppercase lowercase numbers and symbols (same for Proton, for both login and mailbox passwords) I only need to remember 4 20+ character strong passphrases. One for Google (Sandboxed Play), 2 for Proton, and one for Authy, though Authy usually restores from Seedvault with all data so I only need my Authy PIN.
That way from a new install I have access to my Google account, ProtonPass with all TOTP's, and I can unlock my mail, VPN, calendar, encrypted cloud drive and password manager easily!
This way its a high security setup,I can use advanced security features of Proton such as the Proton Sentinel program, which is a program for people with a high threat model (not me but I have it on anyways!) They monitor your account for sketchy activity constantly. I also have all my recovery file, phrase and backup codes in encrypted .7z files on my laptop and phone (only another 4 passwords to memorize, supervisor, boot, login for laptop and password, not PIN for phone!) So very unlikely I'll ever loose data of my Proton account.
That's how I do things. Everyone is different though, just putting this out there since I've found great success with this setup. For me it is very convenient, and I also believe it is quite secure with TOTP and strong passwords in all these accounts. I have fully random 30+ character all (96) character passwords on every other online account! (at least until I get security keys and more passkeys, I have one for Google but I'm leaving my password and TOTP on for now...)