You don’t mention which version of Windows you’re using, but as a user of unsupported SU17 Make relying on an Intel graphics chipset, your options are limited to things that have already been posted throughout this forum about the slow selection tool issue (updating graphics driver, checking that some Windows update made a change to system and/or graphics driver, etc.) There will not be a one-size-fits-all answer because there are so many potential variables between all the different computer set-ups around the world.
A new potential fix that worked for some is changing compatibility mode (one of many tips in the main thread about this selection tool issue.)