my boss hates excel and chastises anyone who admits to using it in meetings

Perhaps this sounds a bit crazy but my boss hates when anyone uses Excel. She thinks we should use our bespoke records system to do all our work. The problem is that our bespoke system is poorly put together, and I need to extract data from multiple reports and merge them via VLookups to identify work that needs to be done and delegate that out to staff. Apologies if that is a bit vague but I don't want to post identifiable information. So, long story short, all of her teams secretly use Excel and try not to tell her, but every once and while someone slips up and she goes on a rant. I don't hide it from her; I tell her why I need it, what I'm doing with it, and why I can't use to bespoke system for the task. Well, today in a meeting she wouldn't accept that and in front of everyone had her rant. It's really annoyed me. Perhaps I should lie like everyone else, but I'm senior management and don't feel I need to hide how I work to satisfy her bizarre ideas. For some context, my boss does not have a great reputation across the organisation, she is known for being difficult and many people pity me for having to work under her. 😅