What is the difference between twtxt-php and timeline from sorenpeter?

twtxt-php is a minimalistic client based on another PHP project, you can see it on https://eapl.mx/twtxt
timeline is a better-looking Web app, with support for markdown, images gallery... you can see it here http://darch.dk/timeline/

twtxt-php is not actively developed, its core was merged into timeline

Does it have a way to follow feeds from the web ui?

Yes, but you have to be logged in. Currently can only add URLs, not edit or unfollow.

I was looking at it and what prevents someone from downloading the .config file and getting the password?

An .htaccess file

Also how would I generate a totp password to use?

That part is missing on the Web side, there is a commented PHP code to do that
https://github.com/eapl-gemugami/twtxt-php/blob/master/libs/TOTP.php#L121

Although you can find a better TOTP onboarding on https://fit.eapl.me