I love the 2.0 update, I'm glad I switched to the portable version. There are a couple of issues when running it on Windows 10 though.
1) "open config file" and "show config file in explorer" buttons do nothing for me. I manually found the file anyways since it's in the same folder as the exe, but still.
2) There is a small visual issue, as shown even in your gifs, that with some themes the "< >" have two small dark dots, which are very visible when using a light color for the "selected entry color" setting.
3) I can't seem to find the pdf manual that other people are talking about in the comments?
Finally two suggestions:
1) it would be nice if the month names were customizable or if they'd follow the spellcheck language (i.e. in my language - Italian - the abbreviations are GFMAMGLASOND instead of JFMAMJJASOND)
2) It would be a QoL improvement if the spellcheck enable/disable and the language picker were in the cogwheel settings instead of having to go to %appdata%\jrnl and manually edit the code. Again not a big issue for some of us, but others might find it bothersome.
All in all I love the software, it's a bit unpolished/tech-savvy but it's really good imho. Most journaling tools for Windows are ugly as hell or absolutely impractical, while this is very aesthetically pleasing and minimal while still being functional.