There is a Feature Request item for rendering cell using custom html. You may cast a vote for its implementation.
As far as the proposed workaround and possible issues with it are concerned, I suppose that it may interfere with Spreadsheet functionalities other than editing. Some of them are client-side and server side Export to Excel/PDF, merged cells, freezing panes, keyboard navigation, resizing rows and columns, as well as most probably filtering, sorting, selection, scrolling. These are some of the scenarios I would suggest to test on your side.
I hope this is helpful.
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