I don’t think there is any specific limit when using tags - in the end, tags are also just plain text within files. They don’t do anything special as long as you don’t click them. If you click them, all that happens is a search being started, just like any other search operation in obsidian that finally relies on obsidian’s cached note content.
As to the question if your tagging system is “rational” - well, that all depends why you use tags and what exactly you want to achieve. Can you describe your aims in more detail?
I, personally, rely a lot on tags. For me, they establish a network of related topics and notes I wouldn’t remember or think of on my own. In doing so, they produce new connections and force me to leave behind or question my conventional, pre-structured ways of thinking. I have advocated the use of (content-related) tagging in more detail here.
In order to achieve my described goal, I heavily rely on the dataview plugin. The template I use for all my Zettelkasten notes contains a dataview query so that, whenever I read any existing note, I am reminded of connected arguments and topics without explicitly searching for them. In a simplified version (mine is a bit more complex), the last part of my template looks like this:
