Hey, thanks for the reply! (And sorry for the late reply, I missed the notifications somehow)
I was discussing with this topic with the developer of Merge Duplicated Symbols plugin, explaining my situation, and I was trying to use the beta for merging text and layer styles, sometimes it works, sometimes it's not. (I wasn't able to identify when it does and when doesn't, but it's still in beta, so yes, my best hopes in his next release.) Here you can see our conversation: https://github.com/oodesign/merge-duplicate-symbols/issues/40
Yes, Automate has a similar feature, the Change Local Text Style to Library Text style, but in reality I couldn't make it work. For example, local style using XXX font, 16pt, 26 line height, 8 paragraph and a hex color, the library style is the same, everything seems the same, but if I try to replace the styles with library style based on Properties, it doesn't show as similar, nor replacing it. I have no clue why, and this is why it'd be nice to have a visual, and non-automated replacer.
Replace library, I used it many times, and it works well when for example the library I'm replacing is just an older version, and the style values, naming or ID are similar, but when it's not finding the match I can't find out why not, and this is where manual replacement would be really useful. I have a hope in oodesign and in his plugin.