Not outside useable range for pool, but odd for sure.
Stalev uses a cue that is approx 28oz, though I presume pool was not his primary introduction to cue sports.
Like 19 oz is pretty average weight for a pool cue 25 oz is tha same average for a piramid cue.
I won't state no way Stalev's piramid cue weight is 28 oz but if so it is at least as much odd as playing pool with 25 oz cue.
What I do know for sure he used to play pool with a cue made by one of the russian cuemakers with similar design, construction, woods (hornbeam stiffer shaft with splices and so on) but it was made specially for his liking in pool and its weight was definitely no more than 25 oz ... less is more likely.
It was more than 15 years ago when me together with young Artem Koshoviy and some other pals and countrymen went to one of the stages of the Russian cup to Sanct-Petersburg.
I do remember that certain cup among the others because it was some fun during the trip to that beautiful city and Stalev participating in that stage made it even more interesting. Artem who was pretty young at the time 14 or 15 y.o. after group stage where we played round robin he got Stalev in a single elimination stage and won. It was a great match up with some great emotions and memories which I filmed on my camera and Artem's parents were glad to watch it later I believe)... Artem had won quite a few those Russian cups and it was very useful experience for him improving as a player at that time.
At that tournament there were some players curious what cue Evgen played and he allowed to try and test hit with some comments on the history of the cue... I don't remember all the details but it was not as heavy as most piramid cues...
Of course I believe it was not the only cue he used to play pool. Great player with some stroke so as De Luna).