Yeah, b) does provide for attribution, which could be a valid claim here. But b) does not prohibit rebranding, nor does it require the use of branding to be used in any trade capacity as described under e).

Referring to a brand in the capacity of providing attribution is entirely different than using a brand in the capacity of trade. Attributing someone is not the same as using their trademark. Ever write a "works cited" at the end of a report in school? They aren't full of logos, they don't imply that you are the author, (they state the opposite) and they certainly don't violate any trade laws. They are literally just lists of attributions.

e.g. "This software is copyright OnlyOffice", or similar, is an attribution that does not violate any trademarks. It satisfies both b) and e). (although I will note that the license says "or" for each of those, but this probably isn't the intended interpretation)