It’s hard for me to tell without replicating your situation on my computer. Since I wrote this post, I’ve installed InDesign on a new Windows 11 machine and I didn’t have to do this Harfbuzz adjustment, it worked fine natively.

The most thorough solution would be for softwares (like InDesign, Word, CSS) to adjust the convert the numbers automatically based on the assigned language of the text. None of them do, unfortunately, and I don’t see this likely in the future. That being the case, the best pragmatic solution I’ve used is that I add a SS1 (opentype stylistic set) to all the fonts I design which converts all Latin numerals to Bengali numerals, and when this stylistic set is assigned to the page/list number style, it shows correctly in Bengali. Unfortunately, this only works for my fonts.