I tried Servo, the undercover web browser engine made with Rust

Firefox is already made in rust though. only sorts it seems. They were founding members though that's the part I remembered.

how long is a piece of string?

sorry. browsers are insanely complex pieces of software. like, operating system level. the standard has grown enough that the web is it's own platform. so your definition of "daily use" is what is important; servo can open web pages, render html and css, and store cookies. it can also do some javascript. that's enough to deal with like 80% of all websites ever written... but not the ones non-technical people use like facebook and twitter.

there's also the matter of what features you actually require: tabs were not a standard feature for the first fifteen or so years of the web. search in the url bar was seen as an antipattern at first and wasn't included. credential storage (like password autofill) wasn't added until like 20 years in.