I have yet to see a slow HTML-only website ;) (which is not 10MB single file spec or entire book). Really, I don't think html parsing is a huge bottleneck and these few parser exceptions don't seem to be that hard to implement - just close a tag if opening one of a predefined list, no backtracking or something expensive.
Depending on what sites you're mostly accessing, it may be worth experimenting with Firefox Mobile plus uBlock Origin plus perhaps one or more of the extra anti-(ad|bloat)ware extensions. Chrome is definitely faster in a straight line but once I've got Firefox configured it's (to me) significantly more pleasant to use (and I like the current UI better than Chrome's though that's -definitely- not a universal opinion, mileage may vary as ever).