Central bank buying bonds and increasing money supply absolutely is inflationary. That is precisely how FOMOs work, with the end goal being increasing or decreasing money supply depending on inflation and labour market. So if you already have stubborn inflation and you have a fiscal crisis then unmooring inflation expectations by lowering rates is exactly what you don't want to do (risk becoming a banana republic that inflates away it's debt). I don't think this will happen in the near future but it is absolutely a risk and you'd be foolish as a central banker not to consider it.