Why "huge mess"? I mean, I understand that LibreOffice Calc doesn't have all the functionality of Excel. What errors have you encountered?
To be honest, I'm using Excel once in a blue moon and mainly using it for adjusting pricetables at my work. LibreOffice Calc also does the work perfectly, so I have no complains on this. Erm... "Had no complains", as I have a 365 subscription on my personal laptop, so I no longer use LibreOffice.
I'm not talking about errors per se. Working with LibreOffice feels to me like the devs never use it themselves.
Maybe it's because I'm used to Excel and so I expect LibreOffice to work in a similar way, but it's just full of small annoyances that really slow you down.
Next time I use it, I'll try to remember to document a list of "bugs".