Hi @Maurycy, I am indeed using v1.1.4.
When describing the size of the wiki, I don’t usually care about shadow tiddlers. As a wiki gets larger, the time needed for filter operations increases, while the time to modify the browser DOM will not. The default input to most filter runs will be all[tiddlers], so shadow tiddlers will be excluded from those, and the time required to calculate these filters will depend mainly on the number of non-shadow tiddlers in the wiki.
I also ran the timing test again on my machine at work, and this is the result (Edge):
This is more than double the runtime on my (fairly new) home machine, and here the difference in lag between Edge and Firefox can really be felt. 50 % of 600 ms (calculating the backlinks) is about a third of a second!
Also see this discussion for some tips and tricks to speed up a wiki that has become slow over time.