Ninja
Hi Pankaj,
That is a little disappointing to hear. There is no point in launching a "new" site with old technology. I understand the front-end can use BS4, but popular Joomla extensions are utilizing BS5 already. And that means we are loading (2) libraries with additional bloat. That's the biggest issue - and some minor styling issues on elements when both are used at same time on same page.
Most importantly, the T4 BS5 core template with the updated off-canvas is so much better than BS4. Blockk is one of the best JA templates and incredibly versatile, and recent. For that reason, I still think it would be a good idea to update it on the new BS5.