Sure.

Do you have more info about regal mode and what it actually does?

(Specifics would be great.)
On the ranting front - the likebook software in its current state (aside some pdf note exporting issues that other people have reported), to me - makes the likebook Mars pretty much the perfect ereader.
I get everything out of it that I want, customization can be employed granularity, fonts can be replaced, soft hyphens work, line spacing works. You get small little details like being allowed to use the Kindle UI, when in the default reader software. I get dropbox syncing. I get a functional note function, exchangeable dictionaries. Customizable kerning (in 100+ steps), and a second reader/parser, that I can throw even at misconfigured books, and have a good reading experience, because it ignores most html tags, and a pdf reflow function thats up there with the best ones out there. And pretty much fully customizable eInk refresh settings for reading comics, or dealing with android apps. I get the best TTS possible, which I can install, because its android based (Ivona was bought up by Amazon an was responsible for voicing Alexa).
And then some (well known in the field) youtube influencer comes along, obviously has looked at the reader for 10 minutes max, fiddles with the only setting you shouldnt fiddle with, because you have no idea what its default setting is (because Boyue didnt give position marks on the overall UI contrast slider (which you never need to actually touch)), then hasnt even put books on the device to test what it does to formating, laments about there only being one english font and comes to his expert conclusion that - obviously no one would buy that reader for the ebook features.
Sorry mate, but if you have probably the best eReader UI out there in front of you, and you dont even notice it, because all that you have done was to set line spacing 'wrong', fiddle with the word spacing slider a little, which was probably the only setting, set properly, on a default book with the default san-serif font, without mentioning, that you could supply any .ttf font you want, close down your channel, delete all your videos, and change your profession.
Oh, I did it again. Dang it..