I think you need to step back a bit here as you seem to have a misunderstanding or two. Most importantly, a telephoto lens will not necessarily give you better macro capabilities than a normal lens. For example, the Canon 18-55 IS STM has a maximum magnification of 0.36×, while the Canon 55-250 IS STM has a maximum magnification of only 0.29× - ie the "equivalent" telephoto lens has less macro capability than the normal lens. Telephoto lenses do have some advantages for macro work, principally that the lens is further from the subject so it's easier to get your lighting set up, but macro capabilities are not intrinsically one of them.

Now we've worked out that a telephoto lens isn't necessarily what you want, the question is "what do you want?" The answer here is actually fairly simple: a dedicated macro lens. Canon make a couple of reasonably priced macro lenses (EF-S 60mm, EF 100mm) and there are also third party manufacturers which give other options. Both the Canon lenses give you "true macro" (i.e. 1:1) reproduction. If you want to go further than that, Canon make the very specialised MP-E 65mm which will give you 5× magnification, but definitely do some reading before buying the lens as it's got a lot of quirks.