As possibly a final comment, I've just left a review on Screwfix, and I've just noticed a very similar review made 4 years ago concerning stainless steel. The reviewer rates performance as poor as I have done. Given the RPM tables I have taken speed I used (2600 RPM) as not the issue causing poor performance in light of the drill diameter (2.5mm). And I've discounted the non use of cooling fluid.
The second link that I posted (bench pillar advice for schools) says that cooling fluid isn't required so such small holes in thin stainless. It does however recommend a centre punch.