Bleed port diameter on Magura HS 11 rim brakes?
The threaded ports on Magura brakes I have worked on are bigger in diameter than Shimano, so the bucket tool in your picture would not fit, don't waste money on one uneccesarily, though you can get kits like that to suit a whole range of different brakes.
However, Magura have a feature called &quot;Easy Bleed Technology&quot; where you only need to put a syringe (minus plunger) into the lever bleed port. There are manuals and other guidance on the website https://www.magura.com/en/components/techcenter/?p=2633  (also https://www.magura.com/media/1742/hs11_hs33_2014_en_06.pdf though you note this is an old version).
This would allow you to do a simple burp of the lever with just a syringe, though I would use original Magura brake fluid to maintain the warranty (&quot;Application.of.not-original.MAGURA.parts.and.lubrication.products&quot; would void the warranty, as will &quot;Incorrect Maintenance&quot;).
Note that in my experience, Magura brakes, especially entry level, have an amount of flex and therefore modulation. This can be good for many users, however it can feel spongy if you are used to a stiffer feel. So if once you have burped the brakes, the brakes stop the wheels well but have plenty of modulation, it may not be due to air in the lines. Just bear that in mind.
It sounds like something you're comfortable doing it but if you have any doubts, no harm in waiting for the bike shop.