IF at all possible, (without plugins or script addons). Could E6 add the ability to follow artists?
Sure it may be a bit more data storage, but unless I don't know if this feature already exists, could it become a thing?
(Just requires some new keys to a SQL profile and a bit of JS/PHP)

aye bud, check this out. It may improve your whole e621 experience for the better
https://e621.net/forum_topics/25872

get tapermonkey, upload the file and BOOM, you can favorite artists, tags, and a lot more features.